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→对称超图 Symmetric hypergraphs
The<math>r(H)</math> of a hypergraph <math>H</math> is the maximum cardinality of any of the edges in the hypergraph. If all edges have the same cardinality ''k'', the hypergraph is said to be ''uniform'' or ''k-uniform'', or is called a ''k-hypergraph''. A graph is just a 2-uniform hypergraph.
The<math>r(H)</math> of a hypergraph <math>H</math> is the maximum cardinality of any of the edges in the hypergraph. If all edges have the same cardinality ''k'', the hypergraph is said to be ''uniform'' or ''k-uniform'', or is called a ''k-hypergraph''. A graph is just a 2-uniform hypergraph.
超图<math>H</math>的<math>r(H)</math>表示该超图中任何一条边的最大'''基数'''。如果所有边具有相同的基数''k''，则称该超图为均匀的或k-均匀的，或称之为k-超图。图只是一个2-均匀的超图。
超图<math>H</math>的<math>r(H)</math>表示该超图中任何一条边的最大'''基数'''。如果所有边具有相同的基数''k''，则称该超图为均匀的或k-均匀的，或称之为k-超图。普通图只是一个2-均匀的超图。
The degree ''d(v)'' of a vertex ''v'' is the number of edges that contain it. ''H'' is ''k-regular'' if every vertex has degree ''k''.
The degree ''d(v)'' of a vertex ''v'' is the number of edges that contain it. ''H'' is ''k-regular'' if every vertex has degree ''k''.
'''顶点'''''v''的'''度'''''d(v)''表示包含该顶点的边的数量。如果每个顶点的度都为''k''，则超图''H''是'''k-正则'''的。
'''顶点'''''<math> v </math>''的'''度'''''<math> d(v)</math>''表示包含该顶点的边的数量。如果每个顶点的度都为''k''，则超图''H''是'''k-正则'''的。
The dual of a uniform hypergraph is regular and vice versa.
The dual of a uniform hypergraph is regular and vice versa.
Two vertices ''x'' and ''y'' of ''H'' are called ''symmetric'' if there exists an automorphism such that <math>\phi(x)=y</math>. Two edges <math>e_i</math> and <math>e_j</math> are said to be ''symmetric'' if there exists an automorphism such that <math>\phi(e_i)=e_j</math>.
Two vertices ''x'' and ''y'' of ''H'' are called ''symmetric'' if there exists an automorphism such that <math>\phi(x)=y</math>. Two edges <math>e_i</math> and <math>e_j</math> are said to be ''symmetric'' if there exists an automorphism such that <math>\phi(e_i)=e_j</math>.
如果存在一个形如<math>\phi(x)=y</math>的自同构，则超图''H''的两个顶点''x''和''y''对称。如果存在一个自同构使得<math>\phi(e_i)=e_j</math>，则称两个边<math>e_i</math>和<math>e_j</math>为对称。
如果存在一个形如<math>\phi(x)=y</math>的自同构，则超图''H''的两个顶点''x''和''y''对称 symmetric。如果存在一个自同构使得<math>\phi(e_i)=e_j</math>，则称两个边<math>e_i</math>和<math>e_j</math>对称。
A hypergraph is said to be ''vertex-transitive'' (or ''vertex-symmetric'') if all of its vertices are symmetric. Similarly, a hypergraph is ''edge-transitive'' if all edges are symmetric. If a hypergraph is both edge- and vertex-symmetric, then the hypergraph is simply ''transitive''.
A hypergraph is said to be ''vertex-transitive'' (or ''vertex-symmetric'') if all of its vertices are symmetric. Similarly, a hypergraph is ''edge-transitive'' if all edges are symmetric. If a hypergraph is both edge- and vertex-symmetric, then the hypergraph is simply ''transitive''.
如果超图的所有顶点都是对称的，则称其为'''顶点可传递的 vertex-transitive''' (或顶点对称的 vertex-symmetric)。类似地，如果超图的所有边都是对称的，则该超图是'''边传递的 edge-transitive'''。 如果一个超图既是边对称的又是顶点对称的，则该超图是'''简单传递的 simply transitive'''。
Because of hypergraph duality, the study of edge-transitivity is identical to the study of vertex-transitivity.
Because of hypergraph duality, the study of edge-transitivity is identical to the study of vertex-transitivity.
由于超图的对偶性，边传递性的研究与顶点传递性的研究是相似的。
==横截面 Transversals==
==横截面 Transversals==