On c+-chromatic graphs with small bounded subgraphs
It is shown that if ZF is consistent then so is ZFC+2ω is as large as you wish + “there is a graph with cardinality and chromatic number (2ω) + such that every subgraph of cardinality ≤2ω has chromatic number ω”.
Mathematics subject classification numbers, 1980/85Primary 03E35 Secondary 04A20
Key words and phrasesChromatic number forcing Martin's axiom
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