Hanns-Martin Teichert

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A d-uniform hypergraph H is a sum hypergraph iff there is a finite S ⊆ IN such that H is isomorphic to the hypergraph H+d (S) = (V, E), where V = S and E = {{v1, . . . , vd} : (i 6= j ⇒ vi 6= vj)∧ ∑d i=1 vi ∈ S}. For an arbitrary d-uniform hypergraph H the sum number σ = σ(H) is defined to be the minimum number of isolated vertices w1, . . . , wσ 6∈ V such(More)
Marek's disease virus (MDV) causes a common lymphomatous and neuropathic disease in domestic chickens and, less commonly, turkeys and quail. It is a member of the alpha-herpesviruses and until now was considered to be strongly cell associated. In 1991, MDV was suggested to be the causative infectious agent of multiple sclerosis (MS) in humans. In a previous(More)
If D = (V,A) is a digraph, its competition hypergraph CH(D) has vertex set V and e ⊆ V is an edge of CH(D) iff |e| ≥ 2 and there is a vertex v ∈ V , such that e = N− D (v) = {w ∈ V |(w, v) ∈ A}. We give characterizations of CH(D) in case of hamiltonian digraphs D and, more general, of digraphs D having a τ -cycle factor. The results are closely related to(More)
A hypergraph H is a sum hypergraph iff there are a finite S ⊆ IN and d, d ∈ IN with 1 < d ≤ d such that H is isomorphic to the hypergraph Hd,d(S) = (V, E) where V = S and E = {e ⊆ S : d ≤ |e| ≤ d ∧ ∑ v∈e v ∈ S}. For an arbitrary hypergraph H the sum number σ = σ(H) is defined to be the minimum number of isolated vertices w1, . . . , wσ 6∈ V such that H ∪(More)