Clarification of Edge-connectivity Menger's theorem












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Edge-connectivity Menger's Theorem: A graph is k-edge-connected if and only if every pair of vertices has k pairwise edge-disjoint (p.e.d.) paths in between.




I can see that the later "k" is actually a lower bound, i.e. there might be more than k p.e.d. paths in between some pairs of vertices. But then, if between all pairs of vertices there are more than k p.e.d. paths, wouldn't the graph be not k-edge-connected? Or is it the case that this construction is simply not possible?










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  • The construction is not possible. What you are saying is merely that if G is k edge connected then G has at most k edge disjoint paths. So you are “proving by contradiction” one direction of the theorem. In fact you are stating that it is obvious and I totally agree. However, the difficulty and beauty of this problem is to show that the converse is also true.
    – Sorin Tirc
    Nov 20 '18 at 21:53
















0















Edge-connectivity Menger's Theorem: A graph is k-edge-connected if and only if every pair of vertices has k pairwise edge-disjoint (p.e.d.) paths in between.




I can see that the later "k" is actually a lower bound, i.e. there might be more than k p.e.d. paths in between some pairs of vertices. But then, if between all pairs of vertices there are more than k p.e.d. paths, wouldn't the graph be not k-edge-connected? Or is it the case that this construction is simply not possible?










share|cite|improve this question






















  • The construction is not possible. What you are saying is merely that if G is k edge connected then G has at most k edge disjoint paths. So you are “proving by contradiction” one direction of the theorem. In fact you are stating that it is obvious and I totally agree. However, the difficulty and beauty of this problem is to show that the converse is also true.
    – Sorin Tirc
    Nov 20 '18 at 21:53














0












0








0








Edge-connectivity Menger's Theorem: A graph is k-edge-connected if and only if every pair of vertices has k pairwise edge-disjoint (p.e.d.) paths in between.




I can see that the later "k" is actually a lower bound, i.e. there might be more than k p.e.d. paths in between some pairs of vertices. But then, if between all pairs of vertices there are more than k p.e.d. paths, wouldn't the graph be not k-edge-connected? Or is it the case that this construction is simply not possible?










share|cite|improve this question














Edge-connectivity Menger's Theorem: A graph is k-edge-connected if and only if every pair of vertices has k pairwise edge-disjoint (p.e.d.) paths in between.




I can see that the later "k" is actually a lower bound, i.e. there might be more than k p.e.d. paths in between some pairs of vertices. But then, if between all pairs of vertices there are more than k p.e.d. paths, wouldn't the graph be not k-edge-connected? Or is it the case that this construction is simply not possible?







graph-theory graph-connectivity






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asked Nov 20 '18 at 21:34









ensbana

282113




282113












  • The construction is not possible. What you are saying is merely that if G is k edge connected then G has at most k edge disjoint paths. So you are “proving by contradiction” one direction of the theorem. In fact you are stating that it is obvious and I totally agree. However, the difficulty and beauty of this problem is to show that the converse is also true.
    – Sorin Tirc
    Nov 20 '18 at 21:53


















  • The construction is not possible. What you are saying is merely that if G is k edge connected then G has at most k edge disjoint paths. So you are “proving by contradiction” one direction of the theorem. In fact you are stating that it is obvious and I totally agree. However, the difficulty and beauty of this problem is to show that the converse is also true.
    – Sorin Tirc
    Nov 20 '18 at 21:53
















The construction is not possible. What you are saying is merely that if G is k edge connected then G has at most k edge disjoint paths. So you are “proving by contradiction” one direction of the theorem. In fact you are stating that it is obvious and I totally agree. However, the difficulty and beauty of this problem is to show that the converse is also true.
– Sorin Tirc
Nov 20 '18 at 21:53




The construction is not possible. What you are saying is merely that if G is k edge connected then G has at most k edge disjoint paths. So you are “proving by contradiction” one direction of the theorem. In fact you are stating that it is obvious and I totally agree. However, the difficulty and beauty of this problem is to show that the converse is also true.
– Sorin Tirc
Nov 20 '18 at 21:53










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