Non-isomorphic connected bipartite simple graphs












0












$begingroup$


How many non-isomorphic connected bipartite simple graphs are there with four vertices?



I got below 3.



enter image description here



Numerically my answer is valid. But is it logically valid?










share|cite|improve this question









$endgroup$












  • $begingroup$
    What was your logic? You've not written how you reached here
    $endgroup$
    – Ankit Kumar
    Dec 25 '18 at 6:11










  • $begingroup$
    Looks correct if you don't care about which named node has which 'function'. For example, in your left example, there are 3 more isomorphic versions were B, C, and D take the 'central place' that A has in your example. Those are isomorphic, but depending on why you need to consider this problem, those might still count as different. See for example en.wikipedia.org/wiki/Cayley%27s_formula, which deals with 'labeled' trees, which is obviously different from the question of unlabled trees.
    $endgroup$
    – Ingix
    Dec 25 '18 at 9:30
















0












$begingroup$


How many non-isomorphic connected bipartite simple graphs are there with four vertices?



I got below 3.



enter image description here



Numerically my answer is valid. But is it logically valid?










share|cite|improve this question









$endgroup$












  • $begingroup$
    What was your logic? You've not written how you reached here
    $endgroup$
    – Ankit Kumar
    Dec 25 '18 at 6:11










  • $begingroup$
    Looks correct if you don't care about which named node has which 'function'. For example, in your left example, there are 3 more isomorphic versions were B, C, and D take the 'central place' that A has in your example. Those are isomorphic, but depending on why you need to consider this problem, those might still count as different. See for example en.wikipedia.org/wiki/Cayley%27s_formula, which deals with 'labeled' trees, which is obviously different from the question of unlabled trees.
    $endgroup$
    – Ingix
    Dec 25 '18 at 9:30














0












0








0





$begingroup$


How many non-isomorphic connected bipartite simple graphs are there with four vertices?



I got below 3.



enter image description here



Numerically my answer is valid. But is it logically valid?










share|cite|improve this question









$endgroup$




How many non-isomorphic connected bipartite simple graphs are there with four vertices?



I got below 3.



enter image description here



Numerically my answer is valid. But is it logically valid?







graph-theory






share|cite|improve this question













share|cite|improve this question











share|cite|improve this question




share|cite|improve this question










asked Dec 25 '18 at 5:43









user3767495user3767495

3888




3888












  • $begingroup$
    What was your logic? You've not written how you reached here
    $endgroup$
    – Ankit Kumar
    Dec 25 '18 at 6:11










  • $begingroup$
    Looks correct if you don't care about which named node has which 'function'. For example, in your left example, there are 3 more isomorphic versions were B, C, and D take the 'central place' that A has in your example. Those are isomorphic, but depending on why you need to consider this problem, those might still count as different. See for example en.wikipedia.org/wiki/Cayley%27s_formula, which deals with 'labeled' trees, which is obviously different from the question of unlabled trees.
    $endgroup$
    – Ingix
    Dec 25 '18 at 9:30


















  • $begingroup$
    What was your logic? You've not written how you reached here
    $endgroup$
    – Ankit Kumar
    Dec 25 '18 at 6:11










  • $begingroup$
    Looks correct if you don't care about which named node has which 'function'. For example, in your left example, there are 3 more isomorphic versions were B, C, and D take the 'central place' that A has in your example. Those are isomorphic, but depending on why you need to consider this problem, those might still count as different. See for example en.wikipedia.org/wiki/Cayley%27s_formula, which deals with 'labeled' trees, which is obviously different from the question of unlabled trees.
    $endgroup$
    – Ingix
    Dec 25 '18 at 9:30
















$begingroup$
What was your logic? You've not written how you reached here
$endgroup$
– Ankit Kumar
Dec 25 '18 at 6:11




$begingroup$
What was your logic? You've not written how you reached here
$endgroup$
– Ankit Kumar
Dec 25 '18 at 6:11












$begingroup$
Looks correct if you don't care about which named node has which 'function'. For example, in your left example, there are 3 more isomorphic versions were B, C, and D take the 'central place' that A has in your example. Those are isomorphic, but depending on why you need to consider this problem, those might still count as different. See for example en.wikipedia.org/wiki/Cayley%27s_formula, which deals with 'labeled' trees, which is obviously different from the question of unlabled trees.
$endgroup$
– Ingix
Dec 25 '18 at 9:30




$begingroup$
Looks correct if you don't care about which named node has which 'function'. For example, in your left example, there are 3 more isomorphic versions were B, C, and D take the 'central place' that A has in your example. Those are isomorphic, but depending on why you need to consider this problem, those might still count as different. See for example en.wikipedia.org/wiki/Cayley%27s_formula, which deals with 'labeled' trees, which is obviously different from the question of unlabled trees.
$endgroup$
– Ingix
Dec 25 '18 at 9:30










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