Hypergraph rewriting

Source code and some documentation. If you want to try something:

op m : 2 -> 1
op d : 1 -> 2
rule frobl : 1*d;m*1 => m;d
rule frobr : d*1;1*m => m;d
plotnormalize d;d*1;d*2;2*m;1*m;m