UnVarGraph

data UnVarSet

emptyUnVarSet

mkUnVarSet

varEnvDom

unionUnVarSet

unionUnVarSets

delUnVarSet

elemUnVarSet

isEmptyUnVarSet

data UnVarGraph

emptyUnVarGraph

unionUnVarGraph

unionUnVarGraphs

completeGraph

completeBipartiteGraph

neighbors

delNode