Аноним

Automorphism: различия между версиями

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'''Automorphism''' ---  автоморфизм (ор)графа.
'''Automorphism''' — ''[[автоморфизм графа|автоморфизм (ор)графа]].''


'''1.'''  For an undirected graph, see ''Isomorphic graphs''.
'''1.'''  For an [[graph, undirected graph, nonoriented graph|undirected graph]], see ''[[Isomorphic graphs]]''.


'''2.''' For a directed graph,  '''automorphism''' is a permutation <math>\alpha</math> of <math>V(G)</math>
'''2.''' For a [[directed graph]],  '''automorphism''' is a permutation <math>\,\alpha</math> of <math>\,V(G)</math>
such  that  the  number  of <math>(x,y)</math>-edges is the same as the number of
such  that  the  number  of <math>\,(x,y)</math>-[[edge|edges]] is the same as the number of
<math>(\alpha(x),  \alpha(y))</math>-edges <math>(x,y \in V(G))</math>. We also speak of the
<math>(\,\alpha(x),  \alpha(y))</math>-edges <math>(x,y \in V(G))</math>. We also speak of the
''' automorphism''' of a graph <math>G</math> with colored edges.  This means a permutation
'''automorphism''' of a graph <math>\,G</math> with colored edges.  This means a permutation
<math>\alpha</math> such that the number of <math>(x,y)</math>-edges is the same as the
<math>\,\alpha</math> such that the number of <math>\,(x,y)</math>-edges is the same as the
number of <math>(\alpha(x), \alpha(y))</math>-edges with any given color.
number of <math>(\,\alpha(x), \alpha(y))</math>-edges with any given color.


The set of all automorphisms of a (di)graph forms a permutation group <math>A(G)</math>.
The set of all automorphisms of a (di)graph forms a permutation group <math>\,A(G)</math>.