Show that a relation R on a set X is symmetric if and only if whenever there is a directed edge from x to y in the digraph of R, there is a directed edge from y to x in the digraph of R.(i don't have the slightest idea how to do this...)

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- Aug 9th 2006, 04:06 AM #1

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- Aug 9th 2006, 07:46 AM #2

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Originally Posted by**kodirl**

Therefore, you can talk about G=(X,R) as a graph. But since R is symmetric on X you have that xy is in R (that means an edge in this digraph) means that yx is in E(G) too because of symetrry (that means an edge in this digraph).