Assign positive integer weights to the edges of a simple graph G (with no isolated edges and vertices) of order at least 3 in such a way that the graph becomes irregular, i.e. the weight sums at the vertices become pairwise distinct. The minimum of the largest weights assigned over all such irregula
The irregularity strength of tP3
✍ Scribed by Lael Kinch; Jenő Lehel
- Publisher
- Elsevier Science
- Year
- 1991
- Tongue
- English
- Weight
- 372 KB
- Volume
- 94
- Category
- Article
- ISSN
- 0012-365X
No coin nor oath required. For personal study only.
✦ Synopsis
Let (a,, . . . , a,, b,, . . . , b,) be the sequence of distinct positive integers such that ai + bi are distinct for i = 1, . . . , t, and different from ai and bj, 1 si s t. Denote by s(t) the minimum of the largest element of these sequences for fixed t. In this note we prove s(t) 2 [(15t -1)/71 and exhibit infinitely many sequences attaining equality. We also show s(t) G I(19 -1)/71 + 1 for every t. As a corollary we obtain that the irregularity strength of the graph G = tP,, the disjoint union of t paths of length 3, is about 5n/7, where n = 3t is the order of G.
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