Neighbor sum distinguishing total chromatic number of planar graphs

Let G = (V(G), E(G)) be a graph and ϕ be a proper k-total coloring of G. Set fϕ(v)=∑uv∈E(G)ϕ(uv)+ϕ(v), for each v ∈ V(G). If fϕ(u) ≠ fϕ(v) for each edge uv ∈ E(G), the coloring ϕ is called a k-neighbor sum distinguishing total coloring of G. The smallest integer k in such a coloring of G is the neighbor sum distinguishing total chromatic number, denoted by χΣ″(G). In this paper, by using the famous Combinatorial Nullstellensatz, we determine χΣ″(G) for any planar graph G with Δ(G) ≥ 13.