58/2012 The hills are calling again

My next course on cryptography, at Kathmandu University, is announced. See : http://www.freewebs.com/profpartha/cryptoKUv2.htm.


57/2012 Greedy and unethical

Greedy and Unethical

You want to buy a suitcase for carrying your stuff in your next voyage. You buy the suitcase, but find that the vendor/maunfacturer has put in some garbage already in the box. The stuff you find there is of no use to you, and it also robs you of the space you need for your own stuff. This is exactly what Seagate does, when you buy a portable external hard disk for your backups.
You are a diehard freedom lover, and cannot tolerate anything from the Micro???? junk pile. You find the whole disk formatted to an obsolete and unpopular format NTFS. The disk contains Micro???? executables which you do not need. You do not appreciate this disgusting and irritating experience. You do not appreciate unwanted things being stuffed on to you. By forcing itself on you, Micro???? is only making a laughing stock of itself. Linux users like me can get rid of Micro???? rubbish. This is what you can do (click for details), to give Micro???? what it deserves.


55/2012 Another legendary genius and his remarkable memory

Albert Einstein and his remarkable memory (or lack of it), are legendary.

There are a few far-fetched stories, like the one about him returning to his office and reading his own “GONE TO LUNCH. BE BACK IN 10 MINUTES” sign.

Or, how he lost his way one day, when going back home. He called up a taxi and told him-- "please take me to Albert Einstein's home" (knowing that all taxi drivers knew the house of a great scientist called Albert Einstein).

54/2012 The stuff that makes great mathematicians

Weiner was in fact very absent minded. The following story is told about him: When they moved from Cambridge to Newton his wife, knowing that he would be absolutely useless on the move, packed him off to MIT while she directed the move. Since she was certain that he would forget that they had moved and where they had moved to, she wrote down the new address on a piece of paper, and gave it to him. Naturally, in the course of the day, an insight occurred to him. He reached in his pocket, found a piece of paper on which he furiously scribbled some notes, thought it over, decided there was a fallacy in his idea, and threw the piece of paper away. At the end of the day he went home (to the old address in Cambridge, of course). When he got there he realized that they had moved, that he had no idea where they had moved to, and that the piece of paper with the address was long gone. Fortunately inspiration struck. There was a young girl on the street and he conceived the idea of asking her where he had moved to, saying, "Excuse me, perhaps you know me. I'm Norbert Weiner and we've just moved. Would you know where we've moved to?" To which the young girl replied, "Yes daddy, mommy thought you would forget."

About Norbert Wiener :: See http://en.wikipedia.org/wiki/Norbert_Wiener


53/2012 Ubunutu lovers will love this......

How to build an exactly similar ubuntu installation on another computer

(I have not yet tried this myself....partha)

Copied from :: http://www.shibuvarkala.com/2012/07/how-to-build-exactly-similar-ubuntu.html

Here is an easy way to build an exactly similar ubuntu installation on another computer. Run $ dpkg --get-selections >my_pakages on the machine that you want to clone. Install a clean copy of Ubuntu on the target machine. Copy the file my_packages to the target machine. Run the following command on the target machine. $ sudo dpkg --set-selections < ./package_names $ sudo apt-get -u dselect-upgrade Done.



51/2012 AI @ KU -- Course Chronicle

Each session = 90 minutes
Session # DateEvents
??10 Aug. 2012 Strike/disturbance in KTM. Sign off. Completed student evaluation report. Vacated office.
2509 Aug. 2012 Evaluation of students. Personal interviews. Viva voce.
2408 Aug. 2012 Fuzzy expert systems continued. Fuzzification-defuzzification examples. Defuzzification approaches. Wrap up. Limits of AI. LAST LECTURE
2306 Aug. 2012 Fuzzy expert systems. Reasoning under uncertainty. Overview of logic -- binary logic, ternary logic, multiple valued logic, infinite valued logic, fuzzy logic. Fuzzy rule base. Fuzzification and defuzzification. Examples.
??05 Aug. 2012 Strike/disturbance in KTM. NO class
??03 Aug. 2012 KU Entrance exam. NO class
??02 Aug. 2012 "Rakhi" -- holiday. NO class.
2230 Jul. 2012 Student seminars. Rohit Amatya "Instant insanity". Chandan Gupta "Prolog features and examples".
2127 Jul. 2012 Student seminars cancelled. Review. General discussions.
2025 Jul. 2012 Robotics and AI overview.
1923 Jul. 2012 Expert systems
1820 Jul. 2012 Seminar on Prolog (Chandan Gupta). Seminar on Simulated annealing (Rohit Man Amatya). Discussions.
1718 Jul. 2012 AI technologies. Overview of : Expert sytems, ANN, Fuzzy logic driven systems, Image processing systems, Banking systems, Intelligent programs, implantable medical devices, intelligent buildings.
1616 Jul. 2012 AI programming. Desirable features. Panorama of languages. Overview of Prolog. Lambda calculus. Overview of LISP. SHRDLU.
1513 Jul. 2012 Seminar on "Semantic graphs" by Sushil Shreshta. Seminar by Rohit Man Amatya on "Non- monotonic reasoning". Discussions.
1411 Jul. 2012 AI in manufacturing.
1309 Jul. 2012 AI in design. Concluding session.
1206 Jul. 2012 Seminar/presentation by Chandan Pd Gupta : Genetic algorithms Discussions.
11a ?? Jul. 2012 AI in engineering. AI in design.
11 04 Jul. 2012 Extension of interval algebra. Events and durations. Episode analysis. Use of constraint logic programming.

AI in engineering. AI in design.
1002 Jul. 2012 Overview of temporal logic methodologies. LTL, LTA, interval algebrs, duration calculus, time Petri nets, hybrid Petri nets, Interval algebra s a semantic net. Use in temporal knowledge base creation. Checking inconsistencies. Post-mortem analysis. Glass oven example.
901 Jul. 2012 Seminar/presentation by Rohit Man Amatya : automated guided vehicles. Discussion on AGV.
827 Jun. 2012 Temporal knowledge and temporal reasoning. What is time ? Why should we bother about time ? Approaches to temporal knowledge : modal logic, LTL, quantified time, events and conditions, relative time, interval algebra.
725 Jun. 2012 Knowledge representation.Principles. Requirements. Precautions. Methods. Lists. Trees. Fault trees. Semantic nets. Rule based systems. Logic based. Relay ladders.
622 Jun. 2012 Seminar/presentation by Chandan GUPTA. Tabu search
520 Jun. 2012 AI problems, characteristics of AI problems, state space, state dependant problems, path dependent problems, search, informed vs uninformed search, heuristic search, depth first, breadth first, back tracking.
418 Jun. 2012 Issues in intelligence vs knowledge. Recognising human intelligence. Turing test. CAPTCHA.

Learning. Objectives. End-results. Learning approaches :: supervised, assisted, Autonomous, unattended. Learning methodologies :: rote learning, Take advice, Learning by example / induction, Explanation based, Discovery, Analogy.
317 Jun. 2012List of topics for seminar/projects. The nature of knowledge. Knowledge vs. intelligence. Knowledge vs. meta-knowledge. Why machines are not intelligent creatures.
213 Jun. 2012Take-off lecture. Course modalities. NLP vs problem solving.
111 Jun. 2012Course planning. Preparations.

Dummy. Test. Ignore

Day #DateEvents
xy This is a dummy table for testing


50/2012 An unforgettable experience

I visited my school, after 46 years. I was transported to my childhood days, as I loitered all around this school. I recalled many moments of joy, anxiety, and discovery, which I had experienced several years ago. Time flies relentlessly. People grow old, but memories remain young. Thank you, my dear school, for what you did to me.

49/2012 Another amazing bookstore

My earlier post # 36/2012 spoke of an amazing bookstore in Oxford, UK. Here, in India, I found another bookstore, which is just as amazing :: The TATA bookhouse in Indian Instt. of Science, Bangalore (Bengaluru for some fanatics). A bookstore where books are piled up from the floor to the ceiling. The place is so small, you wont fall down if you trip over something. You can browse for hours together, until your legs start aching. The things you discover here will make you come for more.
Even the staircase is stacked with books. You wonder how they keep track of all those gems. The remarkable thing I noticed is that, unlike many other bookshops I know, they do not keep any of those dumb "coffee-table books" which you find everywhere. Never mind, they have a real superb coffee house next door where they serve excellent south-Indian coffee and snacks. A visit to Bangalore is not complete without a visit to Tata Book House, and the coffee shop next door.

TATA Book House has a twin sister in IIT Chennai. This one is much bigger, and is much better organised, but it does not impress a book lover, like its Bangalore sister. This bookshop is also located in close proximity to a coffee shop. It is just one floor above "Cafe coffee day". TBH seems to know the formula that book lovers are also great coffee lovers. Good for me !

Thanks to TBH, I am now richer by several great books. I am a happy man !


48 / 2012 Boy or Girl paradox

A simple question in probability theory. The answer is not so simple. Take a look at :: http://en.wikipedia.org/wiki/Boy_or_Girl_paradox to see how mathematics can sometimes be bewildering to many of us.



47 / 2012 Doctor, heal thyself

Doctors are the ones who advise people not to smoke. Doctors are often the ones who go out of their way to adopt sickening and toxic computing practices and platforms (read Microisoft). They find it okay for them, but forget the nuisance their addiction can cause to all around them. Those who are so fussy about keeping themselves clean and sterile in the operation theatre ignore the kind of infection they are creating and spreading in their front office, by using infected and infectable software (read Microsoft).

Here is hope for them, and for mankind. Open "medical records system" Open MRS is just what we can prescribe for the doctor who needs to be cured. Supported by World Health Organization and a host of health organisations the world over, open MRS is just what you need for your front office.

OpenMRS is a multi-institution, non-profit collaborative led by Regenstrief Institute, a world-renowned leader in medical
informatics research, and Partners In Health, a Boston-based philanthropic organization with a focus on improving the lives of underprivileged people worldwide through health care service and advocacy. These teams nurture a growing worldwide network of individuals and organizations all focused on creating medical record systems and a corresponding implementation network to allow system development self reliance within resource constrained environments.

OpenMRS is a software platform and a reference application which enables design of a customized medical records system with no programming knowledge (although medical and systems analysis knowledge is required). It is a common platform upon which medical informatics efforts in developing countries can be built. The system is based on a conceptual database structure which is not dependent on the actual types of medical information required to be collected or on particular data collection forms and so can be customized for different uses.

For more details ::: http://openmrs.org/about/

Doctor, it is time to heal thyself, before you attempt to heal the world.



44/ 2012 MS-Linux under GPL

MS Linux is released under the provisions of the Gates Private License (GPL), which means you can freely use this Software on a single machine without warranty after having paid the purchase price and annual renewal fees.

Read about this and other Microsoft adventures, at ::


43 /2012 Hungary does it again !

The winner of the prestigious Abel Prize of the Norwegian Academy of Science and Letters for the year 2012 is 72-year-old Hungarian mathematician Endre Szemerédi of the Alfréd Rényi Institute of Mathematics, Hungarian Academy of Sciences, Budapest, and Department of Computer Science, Rutgers, The State University of New Jersey in the United States. He gets this award for "his fundamental contributions to discrete mathematics and theoretical computer science, and in recognition of the profound and lasting impact of these contributions on additive number theory and ergodic theory.”

You can see the news report at ::

Hungary has a long reputation for excellence in mathematics, the most famous contributor being Paul Erdos

The extraordinary mathematical talent of Prof. Endre Szemerédi was discovered when he was a young student in Budapest by his mentor, famous Hungarian mathematician Paul Erdõs.



41/2012 Tutorials on modulo airthmetic

I have added two more tutorials on modulo arithmetic. You can download these from :: http://drpartha.org.in/publications/downloadcrypto.htm


40/2012 Vedic Maths ? Beware !

Vedic maths ! Beware !
I came across this incredible advert which claims that your child will become a "maths genius" if you put him in the course on Vedic mathematics which the advertiser was organising.

Don't fall into the trap.

Read the facts about vedic maths, and then take your own decision ::


There are much better ways to make your child a genius in maths.


PS :: Some questions to the advertiser. .

1. When do you call a child a "maths genius" (your own words) ? How do you confirm this ? By what measurements ?.

2. How many of the teachers of this course can themselves be qualified as "maths genius" ? Would they be ready to face a public jury of qualified mathematicians ?


39/2012 Rogue DNS malware --courtesy MSWin32

See my earlier post :: 31/2012 A new threat to the world

What is the point arresting those who created this malware. Why not shoot all the criminals who are responsible for this epidemic ? Start with the perpetrator MSWin32 who makes it easy for such crime to be committed again and again and again. Start with all the dumb asses who help MSWin32 by using the scum bag MSWin32. (Are you one of them ?)

If you are a victim or are wondering if you are a potential victim, take a look at::https://forms.fbi.gov/check-to-see-if-your-computer-is-using-rogue-DNS

Better still, just stop using Win32 and switch over to safer alternatives. Dont let your irresponsible and recklesses choices cause a disaster to innocent users of the w-w-web.


38/2012 Wonder why

Only Feynman can create such things .....

I wonder why. I wonder why.
I wonder why I wonder.
I wonder *why* I wonder why
I wonder why I wonder!

-- Richard Feynman


37/2012 Instant insanity

A tantalising way to teach/learn discrete mathematics (application of graph theory)

Ever wondered how a bunch of four (painted) wooden cubes can teach you discrete maths ?

Try the puzzle called "Instant insanity".

If you dont know about this puzzle, read::


And, if you cant figure out how to solve it, read ::


Thanks to the comment by "nilo de roock" :: Watch this video


36/2012 An amazing bookshop

My last post 35/2012 spoke about how I found a book on the history of mathematics, at Oxford. I found the book I needed, and I also discovered the greatest bookshop of my life.

This incredible bookshop, with a very unimpressive frontage is a place to visit. The shop inside, is stuffed with books, and books and books. There is an endless maze of stairs and corrridors, leading you to stacks and stacks of books. This would be the ideal place to play hide-and-seek, if you are not desperately looking for books.

As usual I wanted to pick up many books. As usual, I was broke. I had to borrow money from my host, Prof. Bernard Carre. I will never forget this visit and the experience of visiting Blackwell's bookshop in Oxford.

35/2012 Woman mathematicians

Woman mathematicians ? YES they exist. How many of them can you name ? I had this same question, a few years ago, and was desperately seeking an answer. Till, one day, when I visited Oxford Univ., with a famous Professor and a friend of mine. I was in fact a guest in his house at Southampton. I managed to a trace a book which gave me the answers.

Life is much more easy now, with the w-w-web. The answer will now come to your mailbox, by itself. Just join the tweets of City University of New York (CUNY). Start here

Now, to answer the main question I posed in the beginning, here is one good answer

Maybe there are many more of them. I let you find them for me, and inform me.

.....added a few minutes later .......

My quest to locate lady mathematicians led me to Prof. Bhama Srinivasan. I have two things in common with her....she is Indian, and she is apparently a Tamilian (like me).


34/2012 An extension to Godel's theorems

Kurt Godel is supposed to have formulated two famous theorems (strictly speaking, a theorem and its corollary) concerning the completeness of mathematics. Or using mathematics to prove itself.

Take a look here, for details ::


An extension to the above (created by me), would be :: "Can I say if I am insane ?" (maybe I am already insane).


33/2012 Insanity and mathematics....

You will really like this presentation. I know one more person who will soon be listed in this presentation. His name starts with a P and he speaks Tamil. http://www.lomont.org/Math/Talks/Mathematics%20and%20Insanity.pdf

32/2012 Why is a new moon not the same as a solar eclipse?

I discovered the answer to an intriguing question I have always had. I asked many people, but no one seemed to know the answer (or rather gave me a convincing answer). Here is the question ::

"Because a new moon occurs when the moon is positioned between the earth and sun, doesn't this also mean that somewhere on the Earth, a solar eclipse (or partial eclipse) is happening?

What, then, is the difference between a solar eclipse and a new moon?"

Want to know the answer ? Go to :::http://astronomy.stackexchange.com/questions/433/why-is-a-new-moon-not-the-same-as-a-solar-eclipse?newsletter=1&nlcode=57597|1d90

To understand the orbit of the moon, take a look here :: http://en.wikipedia.org/wiki/Orbit_of_the_Moon

If you have not understood the ecliptic, you will not understand anything of all this. So, take a look here, first :: http://en.wikipedia.org/wiki/Plane_of_the_ecliptic. You will find a useful animation explaining the ecliptic and the orbits of the earth and planets.

We can never stop learning.



31/2012 A new threat to the world

A new computer Trojan program is doing the rounds now. DNSChanger is a trojan that will change the infected system's Domain Name Server (DNS) settings, in order to divert traffic to unsolicited, and potentially illegal sites. The culprit -- a shabby piece of software called Win32. The cancer can spread to all DNS servers on the Internet which use Win32. This trojan that is named 'PayPal-2.5.200-MSWin32-x86-2005.exe'. Doomsday has only been postponed. It is not yet eliminated.

The real culprits are the thousands of incompetent and irresponsible users who stick to using Win32 in spite of the warnings by well-intentioned and well-informed scholars. You like Win32 go ahead, enjoy it. But you have no business to spread shit on people who want to live in peace. This cancer is spreading because of idiots like you.

If you still dont stop using Win32, you will be doomed, and so will a whole lot of people around you. Wake up and stop the calamity.


PS Let people know about this threat. Spread the word. You can forward this blog post to all around you. And of course you can come out of the curse of Win32 by abandoning it immediately.


29/2012 Mathematical Foundations of Computer Science

Mathematical Foundations of Computer Science (MFCS) is taught in many of our institutions. It is also called as "discrete mathematics". One of the main hurdles in teaching MFCS is about deciding what exactly should be the coverage of this course. Here is an initiative by IEEE to catalogue the contents of MFCS. This effort is available for review at :

The effort is being directed by an Indian, based in India : Nabendu Chaki, University of Calcutta,

My colleague teachers, and people who plan our curricula, are invited to have a look.



28/2012 Flute making

Useful links on "the art of flute making" ::



Mark Shepard’s Flute Page

You can never stop being creative.


27/2012 Math makes you more crazy

In my last blog post, I named one crazy area where I started working recently. I found one more area which I find fascinating:: using maths to design musical instruments. I took the humble "bamboo with a hole" instrument called flute. Here is what I found

Flute Theory and Maths

Blame it on maths, if you find me behaving crazy.


26/2012 In outer space, which side is north ?

It is amazing how much the w-w-web can distract you and entice you into random directions. I am now getting addicted to some fascinating questions about astronomy. Here is one I picked up at ::


The question I am refering to is :: Is there such a thing as “North” in outerspace?
On Earth, North is determined by the magnetic poles of our planet. Is there such a thing as "North" in outerspace? To put it another way, is there any other way for astronauts to navigate besides starcharts? For instance, if an astronauts spaceship were to be placed somewhere (outside of our solar system) in the milkyway galaxy, would there be a way for them to orient themselves?

There is still so much to discover and learn. There is so little time left.



24/2012 Improvements@home

Made some improvements in my home page :: http://propartha.webs.com Added a new page for testing your LaTeX, and added a LaTeX starter page :: http://www.freewebs.com/profpartha/startlatex.htm Take a look. Have fun. partha


23/2012 Guess who came for lunch ?

It is not every day that we get a chance to have lunch with a great personality. Richard Stallman (aka RMS) was in town today, and I got invited to have lunch with him. RMS, as we all know, is the founder of Free Software Foundation, prime mover of the GNU project, and the person who changed the way the world looks at software.

I thank IIITH which organised the event, and my friend Venkatesh Choppella, who got me into this event. This was indeed a memorable day for me.

22/2012 Ignored in India, recognised abroad

As usual, Partha gets recognised once again. Partha is now on the Editorial Board of a reputed international journal published by Elsevier Publishers from UK. People in his own native India are blissfully ignorant of the jewel they have at home. After all, swines do not recognise or appreciate the value of pearls. Partha is not proud of this recognition, he is ashamed of the ignorance of his own compatriots.

The Editorial Board of EAAI is listed here:


Do you realise your mistakes, you swines who ruled over me for 13 years ? Your ignorance and indifference sank the ship you were steering, and drove away people who could have saved you from a calamity.


21/2012 Do you own a telescope ?

NO problem, if you dont have one. You can get a virtual telescope and go star-gazing. You can do it from home, office, school, or anywhere. Do it in broad daylight, if you want. Here is your virtual telescope :: http://www.fourmilab.ch/yoursky/#Telescope

Try CELESTIA :: Celestia is another software bundle which will help you understand how stars and planets work. It is the perfect companion to your virtual telescope.Get Celestia from ::http://www.shatters.net/celestia/


19 / 2012 Two more discoveries

1. A good site for demystifying group theory :: http://rip94550.wordpress.com/2012/01/30/introduction-to-group-theory-and-cyclic-groups/

2, How to add coffe stains on your LaTeX documents, without wasting coffee, or using a mug. You could be nominated for a Nobel prize by LaTeX loving coffee addicts :: http://hanno-rein.de/archives/349



Do you know what ETAOIN SHRDLU means ?

Take a look at:: http://en.wikipedia.org/wiki/ETAOIN_SHRDLU

Computer professionals have their own ETAOIN SHRDLU. For instance it is very common to name a file, variable, or such things as "foo". My own favourite is "jlt" (means just like that). Mathematicains use "lambda" to denote an unknown thing, or unknown place or unknown person.

17/2012 My website parthas.htm in QRcode

I have now a QR code for my website. Here it is , in three different sizes, Use it any way you want !


15/2012 Online event management system +1

Welcome to OpenConf : Peer Review & Conference Management Made Simple. Take a look at ::


14/2012 Online event management

Allsymposium.com is a Free online event & management portal where Students & Academicians benefit by Creating, Configuring (with themes, background etc) ,Sharing with Social networking sites, Online ticketing & Managing user registrations via My Dashboard their events like Seminars, Symposiums,Culturals,Workshops,Conference etc. You can have a look at http://www.allsymposium.com (link)


13/2012 Using LaTeX for maths

LaTeX is frequently used for typesetting mathematically rich text.How many of us know how to do this nicely ?

Here are some useful tips::




12/2012 The Penguin leads the blind

viSparsh (Haptic belt for visually impaired )

viSparsh is a wearable navigation-device, in the form of a waist belt, which helps visually handicapped persons to move around autonomously. viSparsh is a fusion of two words,"vision"and "sparsh" (touch). Created by young engineers from India, under the Young India Fellowship Program of the University of Pennsylvania USA, and mentored by Prof. Rahul Mangharam, (Director, mLAB, Stephen J. Angello Chair of Electrical & Systems Engg, Dept. of Electrical and Systems Engineering, School of Engineering and Applied Science, University of Pennsylvania), this device can be of immense help in a country like India which has a large number of blind persons and low level of resources.

Details of viSparsh can be found at : http://www.visparsh.blogspot.com/

You can also watch a video of viSparsh in action:: http://www.youtube.com/watch?v=KTmGZ6sElnU

The icing on the cake :: ViSparsh uses Linux (Ubuntu 10.10)!

You can contact the visparsh team at :: visparsh@gmail.com


9/2012 It's all in the stars

Post hoc ergo propter hoc

I was reading the book "Astrology, belive it or not ?" by S. Balachandra Rao (Pub.: Navakarnataka Books, Bangalore, India). People who study formal logic, are aware of the term "Post hoc ergo propter hoc". Post hoc ergo propter hoc, Latin for "after this, therefore because of this," is a logical fallacy (of the questionable cause variety) that states, "Since that event followed this one, that event must have been caused by this one." A subtle variant of this fallacious wisdom is the fallacy called "cum hoc ergo propter hoc", in which the chronological ordering of a correlation is insignificant, yet the events are given a cause-effect relationship.

It is commonly seen that we often observe two unrelated events and conclude that one caused the other. This class of examples is sometimes called the "Rooster Syndrome": "believing that the rooster’s crowing causes the sun to rise". Another example of such fallacious logic lies in statements like :: "A black cat crossed my path, so I missed the train" or in the conclusion that "Bob was in the same train as Alan, so Bob is Alan's murderer".

The most ridiculous usage of "Post hoc ergo propter hoc" is in astrology. The bunkum extends to correlating the relentless motion of planets, to earthly phenomena. A planet's position, as seen from the earth, against the backdrop of some arbitrarily chosen bunch of stars decides whether your favourite horse will win the jackpot or not. Planets have always been moving in the skies. People have always been betting on horses. Why not link these two phenomena ? You dont need to know Latin, or know formal logic, to see the farce called astrology.

The day of the week, when a child is born, will decide whether or not he will win the Nobel Prize. "Einstein was born on a Wednesday, so he won the Nobel Prize". How about all those who were born like Einstein, but did not get the Nobel ? Or, all those who got the Nobel Prize but were not born on Wednesday ? Never mind the hard work the surgeon puts in, to save a life. The patient died because the stars were not in the right place or in the mood to let him survive. "It's all in the stars", says the all-knowing astrologer, to console the dead man's widow. By interspersing their discourses with astronomic jargon and mumbo jumbo they can confuse even the staunchest of astronomers.

When will people learn to use common sense ?



8/2012 When was JC born ? A sequel

My blog entry 3/2012 pondered "when was Jesus Christ born?". This entry is a sequel to the question posed in 3/2012.

This article is about a simple problem, not related to any religion or belief. The problem may be simply stated as :: chronologically speaking, which came first, Jesus Christ's (JC) birth, or the start of the Christian Era (Anni Domini) ? If JC was born on Christmas Day (25 Dec.), why does the New Year in Christian Era (Anno Domini) start a whole week later ? So, JC's birthday cannot be given in AD. If AD started before JC's birthday, JC was not even born when AD started. Sounds perplexing. The answer to this enigma is not easy, or fool proof.

Between the two possibilities, the option where JC was born "before" the AD era (CE), seems to be more plausible. The option that the AD era started before JC's birth is clearly a contradiction. But, this is still a conjecture.

The abbreviation A.D. is short for "Anni Domini Nostri Jesu Christi", i.e., "in the year of Our Lord Jesus Christ". Since Muslims, Jews, etc., may not be entirely comfortable with this, the designation "A.D." is now sometimes replaced by the more neutral C.E. (for "Common Era"), and instead of B.C. ("Before Christ") B.C.E. (for "Before Common Era") is sometimes used. The Gregorian Calendar is the calendar which is currently in use in all European and European-influenced countries, and Dionysius Exiguus's system of numbering years A.D. has endured to the present time. The system of numbering years A.D. (for "Anni Domini") was instituted in about the year 527 A.D. by the Roman abbot Dionysius Exiguus, who reckoned that the Incarnation of Jesus had occurred on March 25 in the year 754 a.u.c., with his birth occurring nine months later. Thus the year 754 a.u.c. was designated by him as the year 1 A.D. It is generally thought that his estimate of the time of this event was off by a few years (and there is even uncertainty as to whether he identified 1 A.D. with 754 a.u.c. or 753 a.u.c.).

Originally the Romans numbered years ab urbe condita (auc) , that is, "from the founding of the city" (of Rome, where much of the character of the modern world had its beginnings). Following his conquest of Egypt in 48 B.C. Julius Caesar consulted the Alexandrian astronomer Sosigenes about calendar reform (since the a.u.c. calendar then used by the Romans was completely inadequate to the needs of the emerging empire, which Caesar was poised to command, briefly as it turned out). The calendar which Julius Caesar adopted in the year 709 a.u.c. (what we now call 46 B.C.) was identical to the Alexandrian Aristarchus' calendar of 239 B.C., and consisted of a solar year of twelve months and of 365 days with an extra day every fourth year. It is unclear as to where or how Aristarchus arrived at this calendar, but one may speculate that Babylonian science was involved. 1 January was the established as the start of the year in Rome at the time of the reign of Julius Caesar. That date had apparently no religious significance in ancient Rome. It is said that Julius Caesar wanted to start the year on the vernal equinox or the winter solstice, but the Senate, which traditionally took office on January 1st, wanted to keep January 1st as the start of the year, and Caesar yielded in a political compromise.

To complicate matters further New Year's Day, the first day of the new year, was celebrated in different countries, and sometimes by different groups of people within the same country, on either January 1, March 1, March 25 or December 25. January 1 seems to have been the usual date but there was no standard observed. With the introduction of the Gregorian Calendar in Britain and the colonies New Year's Day was generally observed on January 1.

Thus 1 January has no relationship to the birth of JC. 1 January has no astronomical significance either. There are indications that many years before Caesar, March used to be the start of the year, since the months September-December are named after the Latin names for 7-10.

The question has been raised as to whether the first Christian millennium should be counted from 1 A.D. or from the year preceding it. According to Dionysius the Incarnation occurred on March 25th of the year preceding 1 A.D. (with the birth of Jesus occurring nine months later on December 25th), so it is reasonable to regard that year, rather than 1 A.D. as the first year of the Christian Era. In that case 1 A.D. is the second year, and 999 A.D. is the 1000th year, of the first Christian millennium, implying that 1999 A.D. is the final year of the second Christian millennium and 2000 A.D. the first year of the third.

We don't know the precise date on which Jesus was born. Celebrating his birth on 25 December is an old Christian tradition, but he might just as well have been born on any other date. There is a popular theory that Christians chose 25 December because there was already a pagan celebration of the winter solstice on or near that date, and Christians then simply gave that date a new significance. But in Christianity it does have significance. Jesus (like all Jewish boys) was circumcised exactly one week after his birth. Since we celebrate his birth on 25 December, his circumcision is celebrated on 1 January. This also means that 1 January is the celebration of Jesus' name; according to the Gospel of Luke, "On the eighth day, when it was time to circumcise him, he was named Jesus, the name the angel had given him before he had been conceived." (Luke 2:21)

The year of birth of Jesus can be estimated using two independent approaches: one based on the nativity accounts in the gospels of Matthew and Luke, the other by working backwards from the date of the start of his ministry, when according to the Gospel of Luke he was about thirty years old. Most scholars assume a date of birth between 6 and 4 BC. This strengthens the theory that CE started much after JC's birthday.

It is true that Christ's birthday would be an appropriate date to celebrate New Year, and in the Middle Ages that was not uncommon. In countries like Denmark, the new year started on 25 December before the 13th century (although there are also historical documents that use other dates). But, of course, calendars are easier to manage if the new year starts on the first day of a month rather than the 25th. It is unclear why the Romans chose to move the start of the year to January.

Note : The above article is a collection of statements found in different, scattered sources on the w-w-web. There is no way to certify the authenticity of these statements. There is still a considerable amount of debate on the origin of calendars and eras. The above article should not be considered as a definite answer to any of the issues involved.



7/2012 Don. Knuth answers your questions

An hour long video where Prof. D E Knuth takes questions live.


The video runs for 1h 09 min. and is a 186 MB mp4 file.


6/2012 Don. Knuth unveils the next Tex

June 2010, Calfornia.

TUG 2010: TeX's 25th anniversary included a talk by Prof Donald Knuth on the design features of the next version of Tex which he is working on. Spiced with his characteristic sparks of humour, this is a must-see video for all TeX/LatEx lovers ::


The video runs for 33.43 minutes and comes as a 87.7 MB file in mp4 format.


PS I have downloaded the above file and can send it to genuine TeX/LaTeX practitioners (you bear the postage and copying costs)


5/2012 June 2012 will be longer than June 2011

June 2012 will be longer than June 2011 by one second. This is because of the addition a "leap second" to our clock (UTC). Read more about the "leap second" at ::




4/ 2012 Cryptography at KU -- Question papers

I have uploaded the question papers of the cryptography course (COMP560) held in Kathmandu Univ. Take a look at ::


You can use these questions as self-assessment tests.



3/2012 When was Jesus Christ born ?

The common calendar we all use is the "Common Era" (CE) calendar, known earlier as A.D. (for "Anno Domini") was instituted in about the year 527 A.D. by the Roman abbot Dionysius Exiguus, However, the New Year starts on 1 January, a whole week after the presumed day of birth of Jesus Christ (Christmas, 25 Dec.). So, when exactly was Jesus born (year) ? What date of birth (25 Dec. ????) would his passport show ? A report will follow in my next blog entry. In the meantime, if you have any inputs, please let me know.



2 / 2012 Understanding our Calendar

A very nice and exhaustive study of calendars ::

http://www.hermetic.ch/cal_stud.htm (link)


1 / 2012 Happy New Year -- commemorating a historical blunder

Happy New Year -- commemorating a historical blunder

We have just started a New Year according to our common Gregorian calendar. The earth just completed going around the sun once. We have just seen 366 sunrises, since the last new Year's Day. There goes a story many of us have not heard of, or have forgotten. Early mathematicians who invented the science of "geometry" decided to divide a circle into 360 degrees. The word geometry itself is inspired from geo -- earth, metry-- measurements. They saw the earth going around the sun in some 360 days (according to their crude and primitive measurements).

Although, later this was proved wrong, we continue to stick to the 360 degrees rule of circles (each degree reminds us of one day in earth's annual excursion), a big blunder which the world has accepted since ages. So, every time we celebrate New Year, we must think of this historic blunder which we made several centuries ago.

Subsequent generations of mathematicians, corrected all this, giving rise to a bewildering variety of calendars. A good collection of calendar related information can be found at ::: http://www.hermetic.ch/cal_stud.htm

The science of geometry grew into the science of astronomy (now we start looking at the stars). We have now come to the stage when we can actually hope to visit these celestial bodies. All this started with a faulty premise of 360 degrees to a circle.