Assertion: wheel | /r/CapableOf | supply counterexample
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Source sentences:
text: The wheel W 6 supplied a counterexample to a conjecture of Paul Erdős on Ramsey theory: he had conjectured that the complete graph has the smallest Ramsey number among all graphs with the same chromatic number, but Faudree and McKay (1993) showed W 6 has Ramsey number 17 while the complete graph with the same chromatic number, K 4 , has Ramsey number 18.