Pontryagin duality

Pontryagin duality is a fundamental concept in the field of algebraic topology and functional analysis, particularly concerning the duality between topological groups and their dual groups. Named after the Russian mathematician Lev Pontryagin, the principle provides a framework for understanding the relationships between locally compact abelian groups and their characters. ### Key Concepts: 1. **Locally Compact Abelian Groups**: These are groups that are both locally compact and abelian (commutative).