One Unspoken Rule of Measure Theory

Here's a measure theory trick: when asked to prove that a set of points in $\mathbb{R}$ (or some measure space $X$) has a certain property, try to show that the set of points which does NOT have that property has measure 0! This technique is used quite often.

Related Posts

"Up to Isomorphism"?

The Back Pocket

Need to Prove Your Ring is NOT a UFD?

The Back Pocket

Four Flavors of Continuity

The Back Pocket

Borel-Cantelli Lemma (Pictorially)

The Back Pocket
Leave a comment!