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Non-Jumping Numbers for 4-Uniform Hypergraphs
Authors:Yuejian Peng
Institution:(1) Department of Mathematics and Computer Science, Indiana State University, Terre Haute, IN, 47809
Abstract:Let r≥2 be an integer. A real number α ∈ 0,1) is a jump for r if for any Open image in new window /></a> >0 and any integer <em class=m, mr, any r-uniform graph with n>n0( Open image in new window /></a> ,<em class=m) vertices and at least Open image in new window /></a>  edges contains a subgraph with <em class=m vertices and at least Open image in new window /></a>  edges, where <em class=c=c(α) does not depend on Open image in new window /></a>  and <em class=m. It follows from a theorem of Erd?s, Stone and Simonovits that every α ∈ 0,1) is a jump for r=2. Erd?s asked whether the same is true for r≥3. Frankl and Rödl gave a negative answer by showing that Open image in new window /></a>  is not a jump for <em class=r if r≥3 and l>2r. Following a similar approach, we give several sequences of non-jumping numbers generalizing the above result for r=4.
Keywords:
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