#### Filter Results:

- Full text PDF available (11)

#### Publication Year

1971

2002

- This year (0)
- Last 5 years (0)
- Last 10 years (0)

#### Publication Type

#### Co-author

#### Journals and Conferences

#### Key Phrases

Learn More

- Gottfried Tinhofer
- Computing
- 1986

Two graphsG andG′ having adjacency matricesA andB are called ds-isomorphic iff there is a doubly stochastic matrixX satisfyingXA=BX.Ds-isomorphism is a relaxation of the classical isomorphism relation. In section 2 a complete set of invariants with respect tods-isomorphism is given. In the case whereA=B (ds-automorphism) the main question is: For which… (More)

Synopsis The mathematical basis of graph set analysis of hydrogen-bond patterns in crystals is presented by deening terms and developing tools for its treatment and subsequent implementation in suitable software algorithms. Abstract To provide a foundation for further theoretical and software development of the application of graph sets to patterns of… (More)

Let (G;) be a permutation group of degree n. Let V (G;) be the set of all square matrices of order n which commute with all permutation matrices corresponding to permutations from (G;): V (G;) is a matrix algebra which is called the centralizer algebra of (G;): In this paper we introduce the combinatorial analogue of centralizer algebras, namely coherent… (More)

- Gottfried Tinhofer
- Discrete Applied Mathematics
- 1989

- Luitpold Babel, Ilia N. Ponomarenko, Gottfried Tinhofer
- J. Algorithms
- 1996

- Mikhail E. Muzychuk, Gottfried Tinhofer
- Electr. J. Comb.
- 1998

1 Abstract In this paper we present a time-polynomial recognition algorithm for circulant graphs of prime order. A circulant graph G of order n is a Cayley graph over the cyclic group Z n : Equivalently, G is circulant ii its vertices can be ordered such that the corresponding adjacency matrix becomes a circulant matrix. To each circulant graph we may… (More)

- Gottfried Tinhofer
- Discrete Applied Mathematics
- 1991

- Oliver Bastert, Daniel N. Rockmore, Peter F. Stadler, Gottfried Tinhofer
- Applied Mathematics and Computation
- 2002

Combinatorial optimization problems defined on sets of phylogenetic trees are an important issue in computational biology, for instance the problem of reconstruction a phylogeny using maximum likelihood or parsimony approaches. The collection of possible phylogenetic trees is arranged as a so-called Robinson graph by means of the nearest neighborhood… (More)

- W Hochstt, G Tinhofer, Winfried Hochstt, W Hochstt Attler, Vor Kurzem, Haben R Jamison
- 1993

Zusammenfassung Hamiltonicity in graphs with few P 4 's. In a recent series of articles R. Jamison and S. Olariu developed, starting from an extension of the notion of a cograph, a theory of the decomposition of graphs into P 4-connected components. It turned out in their work that the algorithmic idea to exploit the unique tree structure of cographs can be… (More)

- Mikhail E. Muzychuk, Gottfried Tinhofer
- Electr. J. Comb.
- 2001

In this paper we present a time-polynomial recognition algorithm for certain classes of circulant graphs. Our approach uses coherent configurations and Schur rings generated by circulant graphs for elucidating their symmetry properties and eventually finding a cyclic automorphism.