Geir Dahl

Head of Department - Department of Mathematics
Image of Geir Dahl
Norwegian version of this page
Phone +47-22855835
Room 1029
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Visiting address Ullevål stadion Sognsveien 77 B 0855 OSLO
Postal address Postboks 1053 Blindern 0316 OSLO

Research interests

Combinatorial matrix theory and optimization, in particular combinatorial optimization and relations to convex polyhedra (polyhedral combinatorics). Recent focused activities include majorization order and polytopes, classes of (0,1)-matrices with given line sums, doubly stochastic matrices, interval polytopes, matrix ranking methods in tennis(!) , Birkhoff polytopes, spectral graph theory etc.. My CV is here.

Teaching

MAT1120 Linear algebra  (foreleser ofte sammen med Erik Bedos)

MAT-INF3100 Linear optimization (until 2013: INF-MAT3370)

MAT-INF4110/MAT-INF9110 Mathematical optimization (until 2013: INF-MAT5360/INF-MAT9360)

Tags: Centre of Mathematics for Applications - CMA, Mathematics

Publications

View all works in Cristin

  • Brualdi, R.A. & Dahl, Geir (2017). Alternating sign matrices and polyhedra.
  • Brualdi, R.A. & Dahl, Geir (2017). Alternating sign matrices and related polyhedra.
  • Dahl, Geir (2017). Laplacian energy, threshold graphs and majorization.
  • Dahl, Geir; Ranestad, Kristian & Hole, Arne (2017). Programmering rammer dybdelæring i matematikk. Aftenposten (morgenutg. : trykt utg.).  ISSN 0804-3116.  s 22- 23
  • Andrade, Enide & Dahl, Geir (2016). Combinatorial Perron values.
  • Andrade, Enide & Dahl, Geir (2016). Combinatorial Perron values.
  • Dahl, Geir (2016). Some Topics in Combinatorial Matrix Theory.
  • Dahl, Geir & Brualdi, R.A. (2016). Doubly stochastic matrices and the Bruhat order.
  • Dahl, Geir & Haufmann, Torkel Andreas (2016). Zero-one completely positive matrices and the A(R,S )matrix classes.
  • Haufmann, Torkel Andreas; Agra, Agostinho; Dahl, Geir & Pinheiro, Sofia (2016). The k-regular induced subgraph problem.
  • Agra, Agostinho; Dahl, Geir; Haufmann, Torkel Andreas & Pinheiro, Sofia (2015). Maximal induced k-regular subgraphs.
  • Agra, Agostinho; Dahl, Geir; Haufmann, Torkel Andreas & Pinheiro, Sofia (2015). The k-regular induced subgraph problem for k=1,2.
  • Dahl, Geir (2015). Combinatorial Matrix Theory and Majorization.
  • Dahl, Geir (2015). Majorization, (0,1)-matrices and Laplacian energy..
  • Dahl, Geir (2015). Permutation matrices, doubly stochastic matrices and their L– rays.
  • Dahl, Geir (2014). Majorization and combinatorial matrix theory.
  • Dahl, Geir (2014). Traveling Salesman Problem: En matematisk rundtur.
  • Dahl, Geir & Brualdi, R.A. (2014). Majorization for partially ordered sets.
  • Haufmann, Torkel Andreas & Dahl, Geir (2014). Optimization and classes of completely positive matrices.
  • Dahl, Geir (2013). An introduction to Majorization: theory and applications.
  • Dahl, Geir (2013). Majorization transforms and Ryser’s algorithm.
  • Dahl, Geir (2013). Nytt Munch museum: et SKRIK etter kombinatorikk og geometri!!.
  • Bebiano, Natália; Dahl, Geir; da Silva, José Dias & da Fonseca, Carlos M. (2012). Preface to the Proceedings of the Coimbra Meeting on 0-1 Matrix Theory and Related Topics. Linear Algebra and its Applications.  ISSN 0024-3795.  436(4), s 789- 790 . doi: 10.1016/j.laa.2011.09.028
  • Brualdi, R.A. & Dahl, Geir (2012). An extension of the polytope of doubly stochastic matrices.
  • Dahl, Geir (2012). A taste of Szemerédi's combinatorics.
  • Dahl, Geir (2012). Google: hvordan man blir styrtrik på en matematisk likning!.
  • Dahl, Geir (2012). Lineær algebra, Google og rangering av websider.
  • Dahl, Geir (2012). Majorization, matrix polytopes and combinatorics.
  • Dahl, Geir & Brualdi, R.A. (2012). Generalized Birkhoff polytopes and majorization.
  • Dahl, Geir & Dahl, Kristina Rognlien (2012). Linear optimization and mathematical finance. Preprint series (Universitetet i Oslo. Matematisk institutt). 04 August 2012. Full text in Research Archive.
  • Dahl, Geir (2011). Kombinatorikk på roterommet!.
  • Dahl, Geir (2011). Majorization in matrix theory: a brief introduction and some recent progress.
  • Dahl, Geir (2011). Martingale matrix classes.
  • Dahl, Geir (2010). Majorization and related combinatorial matrix classes.
  • Dahl, Geir (2010). Majorization permutahedra and (0,1)-matrices.
  • Dahl, Geir (2010). Majorization, A(R,S) and related matrix classes.
  • Dahl, Geir (2009). Disjoint congruence classes and an optimization problem.
  • Dahl, Geir (2009). Introduction to optimization and convexity.
  • Dahl, Geir (2009). Majorization and network problems.
  • Dahl, Geir (2008). Majorization in matrix theory: a brief introduction.
  • Dahl, Geir (2008). Matematisk spillteori - analyse av Nash likevekt.
  • Dahl, Geir (2008). Minimum cuts: theory and algorithms.
  • Dahl, Geir (2007). Matematikk og økonomi: fra John Nash ("A Beautiful Mind") til analyse av trafikk i nettverk.
  • Dahl, Geir & Brualdi, R.A. (2007). Some Combinatorial Matrix Problems and Discrete Tomography.
  • Dahl, Geir & Brualdi, R.A. (2007). Some Combinatorial Matrix Problems and Discrete Tomography.
  • Dahl, Geir & Brualdi, R.A. (2006). Constructing (0,1)-matrices with given line sums and certain fixed zeros.
  • Dahl, Geir & Flatberg, Truls (2006). An integer programming approach to image segmentation and reconstruction problems.
  • Dahl, Geir; Flatberg, Truls; Foldnes, Njål & Gouveia, Luis (2006). The Jump Formulation for the Hop-Constrained Minimum Spanning Tree Problem.
  • Dahl, Geir; Leinaas, Jon Magne; Myrheim, Jan & Ovrum, Eirik (2006). A tensor product matrix approximation problem in quantum physics.
  • Dahl, Geir; Ovrum, Eirik; Leinaas, Jon Magne & Myrheim, Jan (2006). A tensor product matrix approximation problem in quantum physics.
  • Dahl, Geir & Brualdi, R.A. (2005). Matrices of zeros and ones and a zero block.
  • Dahl, Geir (2004). A method for approximating symmetrically reciprocal matrices by transitive matrices.

View all works in Cristin

Published Nov. 30, 2010 11:20 PM - Last modified Dec. 22, 2016 10:03 AM

Projects

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Research groups