fact: Definition fplus m acc := if is_zero acc then VLst_to_X m else plus acc (VLst_to_X m).
imports: ATBR(MyFSets MyFSetProperties) ATBR(Common) ATBR(Classes) ATBR(Graph) ATBR(Monoid) ATBR(SemiLattice) ATBR(Numbers) ATBR(Reification)