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Terence Tao

๐Ÿ‘ค Speaker
2047 total appearances

Appearances Over Time

Podcast Appearances

Lex Fridman Podcast
#472 โ€“ Terence Tao: Hardest Problems in Mathematics, Physics & the Future of AI

X times Y is always Y times X, at least for numbers.

Lex Fridman Podcast
#472 โ€“ Terence Tao: Hardest Problems in Mathematics, Physics & the Future of AI

And it's also associative.

Lex Fridman Podcast
#472 โ€“ Terence Tao: Hardest Problems in Mathematics, Physics & the Future of AI

X times Y times Z is the same as X times Y times Z. So these operations obey some laws and they don't obey others.

Lex Fridman Podcast
#472 โ€“ Terence Tao: Hardest Problems in Mathematics, Physics & the Future of AI

For example, X times X is not always equal to X. So that law is not always true.

Lex Fridman Podcast
#472 โ€“ Terence Tao: Hardest Problems in Mathematics, Physics & the Future of AI

So given any operation, it obeys some laws and not others.

Lex Fridman Podcast
#472 โ€“ Terence Tao: Hardest Problems in Mathematics, Physics & the Future of AI

And so we generated about 4,000 of these possible laws of algebra that certain operations can satisfy.

Lex Fridman Podcast
#472 โ€“ Terence Tao: Hardest Problems in Mathematics, Physics & the Future of AI

And our question is, which laws imply which other ones?

Lex Fridman Podcast
#472 โ€“ Terence Tao: Hardest Problems in Mathematics, Physics & the Future of AI

So for example, does commutativity imply associativity?

Lex Fridman Podcast
#472 โ€“ Terence Tao: Hardest Problems in Mathematics, Physics & the Future of AI

And the answer is no, because it turns out you can describe an operation which obeys the commutative law but doesn't obey the associative law.

Lex Fridman Podcast
#472 โ€“ Terence Tao: Hardest Problems in Mathematics, Physics & the Future of AI

So by producing an example, you can show that commutativity does not imply associativity.

Lex Fridman Podcast
#472 โ€“ Terence Tao: Hardest Problems in Mathematics, Physics & the Future of AI

But some other laws do imply other laws by substitution and so forth, and you can write down some algebraic proof.

Lex Fridman Podcast
#472 โ€“ Terence Tao: Hardest Problems in Mathematics, Physics & the Future of AI

So we look at all the pairs between these 4,000 laws, and there's about 22 million of these pairs.

Lex Fridman Podcast
#472 โ€“ Terence Tao: Hardest Problems in Mathematics, Physics & the Future of AI

And for each pair, we ask, does this law imply this law?

Lex Fridman Podcast
#472 โ€“ Terence Tao: Hardest Problems in Mathematics, Physics & the Future of AI

If so, give a proof.

Lex Fridman Podcast
#472 โ€“ Terence Tao: Hardest Problems in Mathematics, Physics & the Future of AI

If not, give a counterexample.

Lex Fridman Podcast
#472 โ€“ Terence Tao: Hardest Problems in Mathematics, Physics & the Future of AI

So 22 million problems, each one of which you could give to an undergraduate algebra student, and they had a decent chance of solving the problem.

Lex Fridman Podcast
#472 โ€“ Terence Tao: Hardest Problems in Mathematics, Physics & the Future of AI

Although there are a few, at least 22 million, there are like 100 or so that are really quite hard, but a lot are easy.

Lex Fridman Podcast
#472 โ€“ Terence Tao: Hardest Problems in Mathematics, Physics & the Future of AI

And

Lex Fridman Podcast
#472 โ€“ Terence Tao: Hardest Problems in Mathematics, Physics & the Future of AI

The project was just to work out, to determine the entire graph, like which ones imply which other ones.

Lex Fridman Podcast
#472 โ€“ Terence Tao: Hardest Problems in Mathematics, Physics & the Future of AI

Yeah, so it would not have been feasible.