narrowSeqStepComplexity :: (Bool,Variant) -> (Bool,Int,Int,Int)
narrowSeqStepComplexity (checked, var@(Variant _ subst)) =
    (not checked, length (varPos var), size subst, length (varsRangeVFresh subst))
narrowSeqStepComplexity :: (Bool,Variant) -> (Bool,Int,Int,Int)
narrowSeqStepComplexity (checked, var@(Variant _ subst)) =
    (not checked, length (varPos var), size subst, length (varsRangeVFresh subst))
narrowSeqStepComplexity (checked, var@(Variant _ subst)) =
    (not checked, length (varPos var), size subst, length (varsRangeVFresh subst))