MathDB

13

Part of 2001 JBMO ShortLists

Problems(1)

Mathematcians at a conference - JBMO Shortlist

Source:

10/30/2010
At a conference there are nn mathematicians. Each of them knows exactly kk fellow mathematicians. Find the smallest value of kk such that there are at least three mathematicians that are acquainted each with the other two.
[color=#BF0000]Rewording of the last line for clarification: Find the smallest value of kk such that there (always) exists 33 mathematicians X,Y,ZX,Y,Z such that XX and YY know each other, XX and ZZ know each other and YY and ZZ know each other.
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