I'll be assuming that you know what these terms mean:

Finding the rank of a matrix (a.k.a a linear function) can be done in polynomial time ($$O(n^3)$$).

It is very difficult to enjoy or appreciate mathematics in a purely passive way—in mathematics there is no real analogy of the role of the spectator, audience, or viewer.

In Hindi and English, question words both have repetitive structure.

In December 2014, I stopped using soap and shampoo. 2 and a half years later, I can confirm that it was a good decision, as my skin has cleared up, my hair is much shinier, and I don't feel oily at all. Plus, it's one less thing to pack.

If a function almost has some nice property, you can quotient out by that property to make that nice property true.

Showing that you're better than your perceived peers is hard work.

I just wrote a Reverse Polish Notation calculator. It's beautiful. Extending a Forth compiler with new words must be a dream.

I find it hard to resist temptation. So I don't.

$$\textbf{Var}(x) = \mathbb{E}[ (X - \mathbb{E}(X) )^2 ] = \mathbb{E}(X^2) - \mathbb{E}(X)^2 $$

1 month ago, I got LASIK. Not a lot of people seem to write about it, so here's one to offset that a bit.

Programmers often hear "read the docs" as advice.

This Garfield strip has a lesson in it.

Planning

Regular expressions are useful enough that they're built in to the syntax of the shell. But they're not always the right tool. Here's my off-the-cuff heuristics for when to use them.

If we consider the exponential notation used in abstract algebra, we get a nice mnemonic for semigroups, monoids, and groups: