Let G be a graph of order n. For every v ∈ V (G), let EG(v) denote the set of all edges incident with v. A signed k-submatching of G is a function f : E(G) −→ {−1, 1}, satisfying f(EG(v)) ≤ 1 for at… (More)

Let G be a graph. A good function is a function f : V (G)→ {−1, 1}, satisfying f(N(v)) ≥ 1, for each v ∈ V (G), where N(v) = {u ∈ V (G) |uv ∈ E(G)} and f(S) = ∑ u∈S f(u) for every S ⊆ V (G). For… (More)