Irreducible real representations of a finite cyclic group (source code)

= Irreducible real representations of a finite cyclic group

For $C_n=\langle g\rangle$, the irreducible real representations are the trivial line, the sign line $g\mapsto-1$ when $n$ is even, and the pairwise nonisomorphic real planes on which $g$ rotates through $2\pi k/n$ for $1\leq k<n/2$.