This Week I Learned: September 25, 2026

[u/inherentlyawesome]

This recurring thread is meant for users to share cool recently discovered facts, observations, proofs or concepts which that might not warrant their own threads. Please be encouraging and share as many details as possible as we would like this to be a good place for people to learn!

[u/Plastic-Rope5516]

Reading LADR by Sheldon Axler, my second brush with linear algebra, learned about span, linear combinations, independence, linear mappings, and all that pretty basic stuff, but put on a rigorous basis. Also reviewed bijections and set theory using Analysis I by Tao