Viswanathan K's Thoughts

On the Internet, there is pretty much no way for a site to know a person’s age. The most obvious kind of sites where this becomes a problem are pornographic sites. Of course, there are other sites which trick and manipulate children on the Internet in other ways. How does one identify and protect minors on the Net?   To try and address this, California passed a law in 2022 making it mandatory for sites to have checks in place to avoid exposing under-age children to certain kinds of content. You’d think it would be hard to argue against this, right? But this was America. A lawsuit was filed against the law, a court granted an injunction. On what grounds? Free speech rights! (In the US, that one is baked into the constitution and many there hold it almost sacred).   Rahul Matthan wrote an interesting post on the matter, contrasting things with India. While the concern of what kids can access and how they are manipulated by web sites holds in India, there are two major d...

At the end of World War II came the “ long divorce ” of physics and maths. Physicists only worked with well-established maths; and mathematicians had no interest in physics. Neither side looked to advances in the other field for new ideas or seeds that might be relevant to their own fields. Why had this happened?   Part of the reason was that mathematicians feared that their field was becoming a “ragtag of unconnected ideas and results”. Kurt Godel’s theorems had struck a dagger at the very heart of maths – maths seemed to be in tatters. Best for mathematicians to decide how their field could proceed, they felt. Another reason was that physicists found they were able to make progress with existing maths. And lastly, applied physics was in vogue, esp. solid state physics. The engineering mindset – approximations were acceptable as long as they worked – was becoming the norm. This, of course, made theoreticians in both physics and maths wary, uncomfortable and even contemptuous o...

There are a lot of unsung heroes. That’s life. But it’s always good to see the odd, sincere acknowledgment of such folks. Shruti Rajagopalan does just that in case of Dr C Rangarajan, the RBI deputy director in 1991 and then the RBI director from 1992-97; along with the bureaucrats and technocrats behind the scenes.   Typically, a country on the verge of bankruptcy (like India in 1991) ends up with a “tin pot currency”. Desperate countries, in such circumstances, take IMF loans. Those loans come with conditions to restructure the economy. The country can’t or won’t restructure (internal pressures, political compulsions, ideological aversion), and so the cycle repeats itself.   India itself went through such cycles in its past. Why didn’t history repeat itself in/after 1991? Because, this time, says Rangarajan, the desire to reform the economy came from within. It was not just something, unlike the last few times, when it was being imposed from outside . As Rangarajan ...

The next part of the physics-maths story starts with quantum mechanics. When Heisenberg tried to explain things, he ran into mathematical array with strange properties. To him, they were strange. Mathematicians, however, had known it for long by the name of array matrices .   Dirac entered the quantum mechanical story late. He was more mathematician than physicist. When he investigated Heisenberg’s and Schrodinger’s equations, he “bent the rule of mathematics”. He made extensive use of a “mathematical function that made purists blanch”. Dirac didn’t care. If the physics worked (as quantum mechanics did), then any mathematical implication of it, however weird it may seem, must be true, argued Dirac. Dirac was reversing the directionality – so far, maths had helped physics; but now Dirac was saying physics could lead to new maths too. Oh, that function that made purists blanch? Decades later, other mathematicians would prove the function was correct.   Dirac wasn’t do...

There are so many who rave about AI, and its many forms like ChatGPT. Yes, the output of many of these AI’s is very impressive. And yes, they hallucinate too (cook up facts). All that’s well known.   What’s less well known is that many AI’s make mistakes with these two simple questions. The first one: Which is bigger? 9.2 or 9.11? The other one is just as simple: How many r’s does the word “strawberry” have?   Believe it or not, a lot of AI’s get those two questions wrong! What is going on? As you know, the AI’s can (on many topics) explain their reasoning. So they were asked to explain how they come to the wrong answers.   On the 9.2 v/s 9.11 question, the AI’s say there are multiple interpretational patterns to evaluate the question. The maths way is just one of them . The maths way leads to the obvious answer (9.2 is the same as 9.20; and so 9.20 or 9.2 is bigger). But there are other ways to look at the question. One such way is to read them as “2” and “...

I was thinking of the entire sequence of events that was set off when Hamas invaded and kidnapped those 100+ Israelis in October, ’23. Since then, in response, Israel has practically wiped out Hamas, bombed Gaza to the ground, attacked Lebanon, weakened Hezbollah enormously, and most recently, attacked Iran’s military leaders and its nuclear sites. A righteous war taken too far? ~~   All this reminded me of a point the standup comedian, Trevor Noah, makes in  his autobiography, Born a Crime . The Holocaust was a terrible and evil act, no doubt. But there have been plenty of other terrible and evil acts through history, many of which are not even disputed. Why is it that the Holocaust gets so much disproportional attention?   A key point, he says, is that the Nazis maintained meticulous records of the numbers and methods they used to exterminate Jews. When the perpetrator maintains records, well, the data cannot be disputed. No such luck for the Africans of Congo...