Genus theory

Genus theory, particularly in the context of algebraic geometry and topology, deals with the concept of genus, which is a topological invariant that characterizes surfaces and, more generally, algebraic varieties. In simpler terms, the genus of a surface refers to the number of "holes" it has. For example: - A sphere has a genus of 0 (no holes). - A torus has a genus of 1 (one hole).