Talk 9: Proof part 1: The perverse filtration

Introduce the notion of Whitney stratified maps and explain how every
algebraic variety and every algebraic map of algebraic varieties admits a Whitney stratification [CM05, Section 3.2]. Introduce the perverse filtra-tion on cohomology and p-splitness and the weight filtration [CM05, Sec-tions 4.2–4.4]. State and sketch a proof of [CM05, Theorem 4.4.4].