Subgroups and Cosets: Lagrange's Theorem

This lecture covers the concepts of subgroups, normal subgroups, and cosets in a group with respect to a subgroup. The dihedral group and Lagrange's theorem are discussed, along with the properties of cyclic groups and relations isomorphic. The lecture also explores the order of groups, generators, and the concept of left cosets. Examples and exercises are provided to illustrate the theoretical concepts.