226 citations
- University of CopenhagenDK15 papers
- National Center for Theoretical SciencesTW10 papers
- National Center for Theoretical Sciences, Physics Division10 papers
- Centre National de la Recherche ScientifiqueFR9 papers
- Instituto de Astrofísica de AndalucíaES8 papers
- European Southern ObservatoryCL6 papers
- Aarhus UniversityDK5 papers
- National Institute of Materials PhysicsRO5 papers
- Utrecht UniversityNL5 papers
- Imperial College LondonGB4 papers
- Space Telescope Science InstituteUS4 papers
- Tokyo Institute of TechnologyJP4 papers
5 papers · 1 filter
Permutations sortable by n-4 passes through a stack
Anders Claesson, Mark Dukes, Einar Steingrimsson
We characterise and enumerate permutations that are sortable by n-4 passes through a stack. We conjecture the number of permutations sortable by n-5 passes, and also the form of a…
Symmetric Schroder paths and restricted involutions
Eva Y. P. Deng, Mark Dukes, Toufik Mansour +1
Let be the set of permutations in the symmetric group with prefix 12. This paper concerns the enumeration of involutions which avoid the set of patterns . We prese…
Vertex coloring acyclic digraphs and their corresponding hypergraphs
Geir Agnarsson, Agust Egilsson, Magnus Mar Halldorsson
We consider vertex coloring of an acyclic digraph $\Gdag$ in such a way that two vertices which have a common ancestor in $\Gdag$ receive distinct colors. Such colorings arise in a…
On Colorings of Squares of Outerplanar Graphs
Geir Agnarsson, Magnus Mar Halldorsson
We study vertex colorings of the square of an outerplanar graph . We find the optimal bound of the inductiveness, chromatic number and the clique number of as a func…
Combinatorial Gray codes for classes of pattern avoiding permutations
W. M. B. Dukes, Mark F. Flanagan, Toufik Mansour +1
The past decade has seen a flurry of research into pattern avoiding permutations but little of it is concerned with their exhaustive generation. Many applications call for exhausti…