Alphabeta Math

Chern and Pontryagin Classes by Splitting and Complexification

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1 · Prerequisites
Abstract Algebra
Algebraic Topology
Category Theory
Combinatorics
Complex Analysis
Coxeter Groups
Homological Algebra
Linear Algebra
Number Theory
Real Analysis
Set Theory
Topology
2 · Logical flowchart

3 · Items

Lemma

The complex orientation of the underlying real bundle

Definition

Complex projective bundle and tautological complex line

Lemma

Integral cohomology ring of complex projective space

Lemma

Cohomology ring of infinite complex projective space

Lemma

The complex tautological Euler class restricts to the projective-fiber generator

Theorem

Integral complex projective bundle theorem

Definition

Chern classes from the projective-bundle relation

Definition

Complex flag bundle and Chern roots

Theorem

Complex splitting principle with integral injective pullback

Theorem

Naturality, normalization, and Whitney sum for Chern classes

Theorem

Uniqueness of Chern classes from the splitting principle

Lemma

The universal complex flag bundle is BT-n

Theorem

Integral cohomology of BU(n)

Theorem

The first Chern class classifies complex line bundles

Proposition

First Chern class of tensor, dual, and conjugate lines

Theorem

Top Chern class equals Euler class of the underlying real bundle

Theorem

Mod-two reduction of Chern classes

Proposition

Complexification is conjugation invariant

Corollary

Odd Chern classes of a complexified real bundle are two-torsion

Definition

Pontryagin classes by complexification

Theorem

Naturality, stability, and mod-two reduction of Pontryagin classes

Theorem

Pontryagin Whitney product away from two

Theorem

Top Pontryagin class is the square of the Euler class

Lemma

The universal oriented sphere-bundle total space has the homotopy type of BSO(n-1)

Lemma

Rational transfer identifies a finite regular cover with deck invariants

Theorem

Rational cohomology of BO and BSO by Pontryagin and Euler classes

Lemma

Cohomology of a finite CW complex vanishes above its dimension

Definition

Chern character of a complex vector bundle

Theorem

Chern character is a natural ring homomorphism on K-zero

Definition

Graded Chern character by suspension and Bott periodicity

Lemma

The graded Chern character respects relative maps and skeletal filtrations

Lemma

Chern character induces the rational isomorphism on AHSS E-two

Theorem

Rational Chern character isomorphism for finite CW complexes

Sources