Every Monday*, the Math Forum staff gets together to talk about math. We call these meetings Math Monday. That’s where we vet new problems and resources, learn about new math and problem-solving strategies, look at how students have solved problems, think up new mathematical questions, etc.

This blog brings Math Monday to the general public. We’ll post problem scenarios in search of questions, interesting math we encounter that we might want to use in a PoW someday, student work that inspires us, and anything else PoW-related we can think of.

Math Monday works because we all contribute. This blog will work if you contribute too. Read the posts, the other comments, and leave your thoughts in a comment as well!

*well, we aim for Mondays. Math Monday sometimes falls on a Thursday which feels weird.

let A be the sigma-algebra generated by all open and dens subset of R.is a APROPER sub set of the Borel sigma -algebra?

I asked on Twitter and Chris Lusto responded: “I think “no”. The only open sets in R are intervals, and the sig-alg generated by intervals = the Borel Alg. So A is a subset, but not a proper one. I *think*. Have a real mathematician check that out.”