Fan of the projective line
= Fan of the projective line
The fan $\{0,\mathbb R_{\geq0},\mathbb R_{\leq0}\}$ defines the <complex projective line> $\mathbb P^1$.
= Fan of the projective line
The fan $\{0,\mathbb R_{\geq0},\mathbb R_{\leq0}\}$ defines the <complex projective line> $\mathbb P^1$.