Universal Graphs without Large Cliques

The theory of universal graphs originated from the observation of R. Rado [4,5] that a universal countable graph X exists, i.e., X is countable and isomorphically embeds every countable graph. He also showed that under GCH, there is a universal graph in every infinite cardinal. Since then, several results have been proved about the existence of universal elements in different classes of graphs....

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Universal Graphs without Large Cliques

The theory of universal graphs originated from the observation of R. Rado [4,5] that a universal countable graph X exists, i.e., X is countable and isomorphically embeds every countable graph. He also showed that under GCH, there is a universal graph in every infinite cardinal. Since then, several results have been proved about the existence of universal elements in different classes of graphs....

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On universal graphs without cliques or without large bipartite graphs

For every uncountable cardinal A, suitable negations of the Generalized Continuum Hypothesis imply: (a) There is no universal Ka 3. The instance Kuf^>t for A = Ni was settled in [KP] from a strengthening of CH.

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A ug 1 99 3 Universal graphs without large cliques

The theory of universal graphs originated from the observation of R. Rado [4,5] that a universal countable graph X exists, i.e., X is countable and isomorphically embeds every countable graph. He also showed that under GCH, there is a universal graph in every infinite cardinal. Since then, several results have been proved about the existence of universal elements in different classes of graphs....

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Large Topological Cliques in Graphs Without a 4-Cycle

Mader asked whether every C4-free graph G contains a subdivision of a complete graph whose order is at least linear in the average degree of G. We show that there is a subdivision of a complete graph whose order is almost linear. More generally, we prove that every Ks,t-free graph of average degree r contains a subdivision of a complete graph of order r 1 2 + 1 2(s−1).

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Universal Graphs without Large Cliques

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