axSubDef = mkBinAxiom "SubDef" typeNatSubTyCon $
              \x y -> fmap num (minus x y)
axSubDef = mkBinAxiom "SubDef" typeNatSubTyCon $
              \x y -> fmap num (minus x y)
axSubDef = mkBinAxiom "SubDef" typeNatSubTyCon $
              \x y -> fmap num (minus x y)