Consider the following bipartite graph $G$, given by $V(G)= \{ s_1,s_2,s_3 \} \cup \{t_1,t_2\}$ and $E(G)=\{ \{ s_1,t_1\},\{s_1,t_2\},\{s_2,t_1\},\{s_2,t_2\},\{s_3,t_2\} \}.$
I want to define the toric edge ring of $G$, that is $K[s_1t_1,s_1t_2,s_2t_1,s_2t_2,s_3t_2],$ in Macaulay2 ($K$ is a field). Do you know a way?
The following doesn't work:
R=QQ[s_1..s_3,t_1,t_2];
S=K[s_1*t_1,s_1*t_2,s_2*t_1,s_2*t_2,s_3*t_2];