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#1 2009-05-19 06:27:06
- GemmaJ1988
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- Registered: 2008-10-08
- Posts: 39
combinatorics
Hey i've been doing some last minute revison and ive stumbled across this question on a past exam paper. Does anyone know how i'd go about answering this my lecture notes dont seem to cover this type of question
Please help 
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#2 2009-05-19 09:38:10
- Avon
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- Registered: 2007-06-28
- Posts: 80
Re: combinatorics
I assume that by
you mean the chromatic number of which I would normally denote .Suppose we have coloured H with d colours and we want to extend this to a colouring of G. Since G cannot be coloured with d colours we need to use a new colour for the vertex x. What does this tell you about the colours of the neighbours of x?
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