What it is
Cards for keeping graduate analysis in working memory: sequences and limits, continuity and compactness, sigma-fields, measures and Carathéodory extension, measurable functions, the integral and its convergence theorems, and the L^p machinery.
Why cards for proofs?
You don't memorise proofs — you memorise the move that starts them. These cards prompt the key hypothesis, the pivotal lemma, or the standard counterexample (yes, the Vitali set is in there), so the full argument reconstructs itself.
Pairs well with
The Measure Theory notes sold in the notes corner — same material, linear form.