Two graphs $G$ and $G^{\prime}$ are said to be graph isomeric if the share the same number of vertices and edges. If there is a graph homomorphism $h \colon G \to G^{\prime}$ between graph isomers which preserves vertex degree, can one conclude that $G$ and $G^{\prime}$ are graph isomorphic?
Graph Isomerism and Isomorphism
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graph-theory
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1I'm using [this](http://en.wikipedia.org/wiki/Graph_homomorphism) definition of homomorphism. – 2012-08-06
1 Answers
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$1-2-1 \quad 1-2-1$
is not isomorphic with $1-1 \quad 1-2-2-1$
But they are isomeric and there is a trivial homomorphism. There are plenty of other examples...
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42-3-2 and 3-2-2, just complete with 1s where needed... – 2012-08-06