Question about isomorphism between two graphs











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If two graphs are isomorphic then does there always exist one vertex $uin A,vin B$ such that removal of this vertices from respective graphs still gives isomorphism? I tried to find contradiction by example with no success.Then I think it is possible every time by picking maximum degree vertex from both and remove it. Am I right?










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    If two graphs are isomorphic then does there always exist one vertex $uin A,vin B$ such that removal of this vertices from respective graphs still gives isomorphism? I tried to find contradiction by example with no success.Then I think it is possible every time by picking maximum degree vertex from both and remove it. Am I right?










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      up vote
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      down vote

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      If two graphs are isomorphic then does there always exist one vertex $uin A,vin B$ such that removal of this vertices from respective graphs still gives isomorphism? I tried to find contradiction by example with no success.Then I think it is possible every time by picking maximum degree vertex from both and remove it. Am I right?










      share|cite|improve this question















      If two graphs are isomorphic then does there always exist one vertex $uin A,vin B$ such that removal of this vertices from respective graphs still gives isomorphism? I tried to find contradiction by example with no success.Then I think it is possible every time by picking maximum degree vertex from both and remove it. Am I right?







      graph-theory






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      edited Nov 17 at 1:36









      Parcly Taxel

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      asked Nov 17 at 1:11









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          Let $f:V_Ato V_B$ be a bijection between the vertices of $A$ and those of $B$. Because this is an isomorphism, any subset of vertices $A'in V_A$ induces a subgraph isomorphic to that induced by $B'=f(A')in V_B$. In the case where $A'$ contains all but one vertex, the desired conclusion is obtained.






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            Let $f:V_Ato V_B$ be a bijection between the vertices of $A$ and those of $B$. Because this is an isomorphism, any subset of vertices $A'in V_A$ induces a subgraph isomorphic to that induced by $B'=f(A')in V_B$. In the case where $A'$ contains all but one vertex, the desired conclusion is obtained.






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              Let $f:V_Ato V_B$ be a bijection between the vertices of $A$ and those of $B$. Because this is an isomorphism, any subset of vertices $A'in V_A$ induces a subgraph isomorphic to that induced by $B'=f(A')in V_B$. In the case where $A'$ contains all but one vertex, the desired conclusion is obtained.






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                Let $f:V_Ato V_B$ be a bijection between the vertices of $A$ and those of $B$. Because this is an isomorphism, any subset of vertices $A'in V_A$ induces a subgraph isomorphic to that induced by $B'=f(A')in V_B$. In the case where $A'$ contains all but one vertex, the desired conclusion is obtained.






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                Let $f:V_Ato V_B$ be a bijection between the vertices of $A$ and those of $B$. Because this is an isomorphism, any subset of vertices $A'in V_A$ induces a subgraph isomorphic to that induced by $B'=f(A')in V_B$. In the case where $A'$ contains all but one vertex, the desired conclusion is obtained.







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                answered Nov 17 at 1:21









                Parcly Taxel

                41k137198




                41k137198






























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