who can explane it more clearly!!
thank you!!

Look at discussion in prevoius topic ("Clarification") on this board. If you still cann't understand - try another problem - this one is not yours :)

this problem is not yours ??? this problem has an ambigous text; it should be changed.

Indeed, I also first thought about the unambiguous representation of a graph by specifying the set of pairs of it's edges that share a common vertex. It's an interesting problem, certainly much more difficult than the original, and the problem statement is at least vague, if not incorrect.

"You are to define if it is possible to present it by the set of pairs of adjacent edges (having a common vertex)".

Presenting means finding a representation. "Present by set of pairs of adjacent edges" is *not* the same as "divide the set of edges into a set of pairs of adjacent edges".

On the other hand, the name of the problem really helps - any search on Decomposition brings to partitioning, not representing, so the problem statement is sufficient in a way.