Characterizations of Additively Graceful Signed Paths and Cycles

Document Type : Original paper

Authors

School of Physical and Applied Sciences, Goa University, Taleigao Plateau, Goa 403206, India

Abstract

A (p,m,n) signed graph S, is a signed graph of order p with m positive edges and n negative edges. In this paper, we first prove a few basic results on vertex labelings of paths. We use these results and a sequence of lemmas to obtain a characterization of additively graceful signed paths. We prove that, apart from exactly 4 exceptions, additively graceful signed paths are characterized by the signed paths containing at most one negative section with n2. We also establish a characterization of additively graceful signed cycles. We prove that a (p,m,n) signed cycle S is additively graceful if and only if one among the following 4 conditions are satisfied, (a) n=0 and m0 or 3(mod4),  (b) n=1 and m1 or 2(mod4),  (c) n=2, m1 or 2(mod4) and S contains a single negative section,  (d) S is the all negative signed cycle on C3.
 

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