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Generating simplicial trees (equivalently, totally balanced hypergraphs) on n vertices

  • A facet F of a simplicial complex is called a leaf if either F is the only facet of Δ, or there exists a facet GΔF such that
    F(HΔFH)G.

  • A connected simplicial complex Δ is a tree if every nonempty subcollection (that is, a subcomplex of Δ whose facets are also facets of Δ) has a leaf.

In the language of simplicial complexes, simplicial trees are equivalent to totally balanced hypergraphs [see Theorem 3.2 of [Herzog, Jürgen; Hibi, Takayuki; Trung, Ngô Viêt; Zheng, Xinxian, Standard graded vertex cover algebras, cycles and leaves, Trans. Am. Math. Soc. 360, No. 12, 6231-6249 (2008)].

A hypergraph is called totally balanced if every cycle C in H of length at least 3 (not necessarily odd-length) has an edge containing at least three vertices of C. A cycle in a hypergraph is a sequence of distinct vertices and hyperedges (v1,e1,v2,e2,,vk,ek,vk+1=v1), where every vertex vi is contained in both ei1 and ei. The number k is called the length of the cycle.

My question. Is there any code in SageMath to generate all simplicial trees (equivalently, totally balanced hypergraphs) on n vertices, having as output the list of hyperedges, and ideally also some visual representation?

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Generating simplicial trees (equivalently, totally balanced hypergraphs) on n vertices

  • A facet F of a simplicial complex is called a leaf if either F is the only facet of Δ, or there exists a facet GΔF such that
    F(HΔFH)G.

  • A connected simplicial complex Δ is a tree if every nonempty subcollection (that is, a subcomplex of Δ whose facets are also facets of Δ) has a leaf.

In the language of simplicial complexes, simplicial trees are equivalent to totally balanced hypergraphs [see Theorem 3.2 of [Herzog, Jürgen; Hibi, Takayuki; Trung, Ngô Viêt; Zheng, Xinxian, Standard graded vertex cover algebras, cycles and leaves, Trans. Am. Math. Soc. 360, No. 12, 6231-6249 (2008)].

A hypergraph is called totally balanced if every cycle C in H of length at least 3 (not necessarily odd-length) has an edge containing at least three vertices of C. A cycle in a hypergraph is a sequence of distinct vertices and hyperedges (v1,e1,v2,e2,,vk,ek,vk+1=v1), where every vertex vi is contained in both ei1 and ei. The number k is called the length of the cycle.

My question. Is there any code in SageMath to generate all simplicial trees (equivalently, totally balanced hypergraphs) on n vertices, having as output the list of hyperedges, and ideally also some visual representation?

Generating simplicial trees (equivalently, totally balanced hypergraphs) on n vertices

  • A facet F of a simplicial complex is called a leaf if either F is the only facet of Δ, or there exists a facet GΔF such that
    F(HΔFH)G.

  • A connected simplicial complex Δ is a tree if every nonempty subcollection (that is, a subcomplex of Δ whose facets are also facets of Δ) has a leaf.

In the language of simplicial complexes, simplicial trees are equivalent to totally balanced hypergraphs [see Theorem 3.2 of [Herzog, Jürgen; Hibi, Takayuki; Trung, Ngô Viêt; Zheng, Xinxian, Standard graded vertex cover algebras, cycles and leaves, Trans. Am. Math. Soc. 360, No. 12, 6231-6249 (2008)].

A hypergraph is called totally balanced if every cycle C in H of length at least 3 (not necessarily odd-length) has an edge containing at least three vertices of C. A cycle in a hypergraph is a sequence of distinct vertices and hyperedges (v1,e1,v2,e2,,vk,ek,vk+1=v1), where every vertex vi is contained in both ei1 and ei. The number k is called the length of the cycle.

My question. Is there any code in SageMath to generate all simplicial trees (equivalently, totally balanced hypergraphs) hypergraphs on n vertices, having as output the list of hyperedges, and ideally also some visual representation?