Geir Dahl

Head of Department - Department of Mathematics
Image of Geir Dahl
Norwegian version of this page
Phone +47-22855835
Room 1015
Username
Visiting address Moltke Moes vei 35 Niels Henrik Abels hus 0851 OSLO
Postal address Postboks 1053 Blindern 0316 OSLO

Research interests

Combinatorial matrix theory; so the study of certain classes of matrices from a combinatorial point of view, or geometric, using convexity and polyhedral theory. 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  (I often lecture this course with Erik Bedos)

MAT3100 Linear optimization 

MAT4120/MAT9120 Mathematical optimization

Reading course in different topics: graph theory, convexity, matrix theory

Tags: Mathematics, Centre of Mathematics for Applications - CMA

Publications

View all works in Cristin

  • Dahl, Geir; Andrade, Enide & Ciardo, Lorenzo (2018). Combinatorial Perron Parameters and Trees.
  • Dahl, Geir & Brualdi, R.A. (2018). Alternating Sign Matrices, Polyhedra and Majorization.
  • 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.

View all works in Cristin

Published Nov. 30, 2010 11:20 PM - Last modified Sep. 18, 2018 7:20 PM

Projects

No ongoing projects

Research groups