Geir Dahl
Academic Interests
Mathematical optimization, in particular integer and linear optimization and relations to convex polyhedra (polyhedral combinatorics). Linear algebra/matrix theory, in particular majorization and combinatorial matrix theory, e.g. majorization, polyhedra and combinatorial matrix classes.
Teaching
- MAT 1120 Linear algebra
- INF-MAT 3370 Linear optimization
- INF-MAT 5360 Mathematical optimization
- Bachelor program Matematikk og økonomi
Higher education and employment history
Professor of Mathematics, Dept. of Mathematics and Dept. of
Informatics, University of Oslo. Previously: associate prof. (UiO) and scientist Norwegian Telecom Research and Inst. for Energy Technology.
Dr. Philos. (PhD), 1992, University of Oslo (Norway), mathematical
optimization. Master of Science, 1983, University of Oslo, mathematical
statistics. Master of Business and Adm., 1982, BI, Oslo.
Cooperation
Richard A. Brualdi (University of Wisconsin), Mike O. Ball (University of Maryland), Carlo Mannino (University of Rome) and others.
Publications
- Dahl, Geir & Brualdi, R.A. (2012). Majorization classes of integral matrices. Linear Algebra and its Applications. ISSN 0024-3795. 436, s 802- 813
- Dahl, Geir (2011). Polytopes related to interval vectors and incidence matrices. Linear Algebra and its Applications. ISSN 0024-3795. 435(11), s 2955- 2960 . doi: 10.1016/j.laa.2011.05.026
- Dahl, Geir (2010). Majorization permutahedra and (0,1)-matrices. Linear Algebra and its Applications. ISSN 0024-3795. 432(12), s 3265- 3271 . doi: 10.1016/j.laa.2010.01.024
- Dahl, Geir & Minken, Harald (2010). A note on permutations and rank aggregation. Mathematical and computer modelling. ISSN 0895-7177. 52(1-2), s 380- 385 . doi: 10.1016/j.mcm.2010.02.052
- Dahl, Geir (2009). Disjoint congruence classes and a timetabling application. Discrete Applied Mathematics. ISSN 0166-218X. 157(8), s 1702- 1710 . doi: 10.1016/j.dam.2008.11.015
- Dahl, Geir (2009). Permutation matrices related to Sudoku. Linear Algebra and its Applications. ISSN 0024-3795. 430(8-9), s 2457- 2463 . doi: 10.1016/j.laa.2008.12.023
- Dahl, Geir; Ball, Michael & Vossen, Thomas (2009). Matchings in Connection with Ground Delay Program Planning . Networks. ISSN 0028-3045. 53(3), s 293- 306 . doi: 10.1002/net.20272
- Dahl, Geir & Flatberg, Truls (2009). Reconstructing (0,1)-matrices from projections using integer programming. Computational optimization and applications. ISSN 0926-6003. 42(1), s 141- 154 . doi: 10.1007/s10589-007-9116-y
- Dahl, Geir (2008). Transportation matrices with staircase patterns and majorization. Linear Algebra and its Applications. ISSN 0024-3795. 429(7), s 1840- 1850
- Dahl, Geir & Minken, Harald (2008). Methods based on discrete optimization for finding road network rehabilitation strategies . Computers & Operations Research. ISSN 0305-0548. 35(7), s 2193- 2208 . doi: 10.1016/j.cor.2006.10.015
- Brualdi, R.A. & Dahl, Geir (2007). Constructing (0,1)-matrices with given line sums and certain fixed zeros. , In Gabor Herman & Attila Kuba (ed.), Advances in Discrete Tomography and its Applications. Birkhäuser Verlag. ISBN 0-8176-3614-5. 6.
- Dahl, Geir (2007). A note on a parameter relating traffic equilibria and system optimal routing. Applied Mathematics and Computation. ISSN 0096-3003. 191, s 445- 450
- Dahl, Geir (2007). Combinatorial properties of Fourier-Motzkin elimination . The Electronic Journal of Linear Algebra. ISSN 1081-3810. 16, s 334- 346
- Dahl, Geir (2007). Majorization and distances in trees . Networks. ISSN 0028-3045. 50(4)
- Dahl, Geir & Flatberg, Truls (2007). An Integer Programming Approach to Image Segmentation and Reconstruction Problems , In Geir Hasle; Knut-Andreas Lie & Ewald Gunther Quak (ed.), Geometric Modelling, Numerical Simulation, and Optimization: Applied Mathematics at SINTEF. Springer Publishing Company. ISBN 978-3-540-68782-5. Part III Optimization. s 461 - 481
- Dahl, Geir & Flatberg, Truls (2007). Reconstructing (0,1)-matrices from projections using integer programming . Computational optimization and applications. ISSN 0926-6003. s 141- 154
- Dahl, Geir; Leinaas, Jon Magne; Myrheim, Jan & Ovrum, Eirik (2007). A tensor product matrix approximation problem in quantum physics. Linear Algebra and its Applications. ISSN 0024-3795. 420(2-3), s 711- 725 . doi: 10.1016/j.laa.2006.08.026
- Dahl, Geir & Brualdi, R.A. (2006). The Bruhat shadow of a permutation matrix, In Olga Azenhas; Antonio Duarte; Joao Queiro & Ana Santana (ed.), Mathematical papers in honour of Eduardo Marques de Sa. Textos de Matematica, Departamento de Matematica. ISBN 978-972-8564-43-8. kapittel. s 25 - 38
- Dahl, Geir & Foldnes, Njål (2006). LP based heuristics for the multiple knapsack problem with assignment restrictions. Annals of Operations Research. ISSN 0254-5330. 146(1), s 91- 104
- Dahl, Geir; Gouveia, Luis & Requejo, Christina (2006). On formulations and methods for the hop-constrained minimum spanning tree problem, In Mauricio Resende & Panos Pardalos (ed.), Handbook of Optimization in Telecommunications. Springer Publishing Company. ISBN 0-387-30662-5. 19.
- Dahl, Geir; Huygens, David; Mahjoub, A. Ridha & Pesneau, Pierre (2006). On the k edge-disjoint 2-hop-constrained paths polytope. Operations Research Letters. ISSN 0167-6377. 34(5), s 577- 582
- Dahl, Geir (2005). A method for approximating symmetrically reciprocal matrices by transitive matrices. Linear Algebra and its Applications. ISSN 0024-3795. 403, s 207- 215
- Dahl, Geir & Brualdi, R.A. (2005). Matrices of zeros and ones with given line sums and a zero block. Electronic Notes in Discrete Mathematics. ISSN 1571-0653. 403, s 207- 215
- Dahl, Geir & Flatberg, Truls (2005). A remark concerning graphical sequences. Discrete Mathematics. ISSN 0012-365X. 304(1-3), s 62- 64
- Dahl, Geir & Flatberg, Truls (2005). Optimization and Reconstruction of hv-convex (0,1)-matrices.. Discrete Applied Mathematics. ISSN 0166-218X. 151, s 93- 105
- Dahl, Geir (2004). On the directed hop-constrained shortest path problem. Operations Research Letters. ISSN 0167-6377. 32, s 15- 22
- Dahl, Geir (2004). Tridiagonal doubly stochastic matrices. Linear Algebra and its Applications. ISSN 0024-3795. 390, s 197- 208
- Dahl, Geir & Flatberg, Truls (2004). Some constrained partitioning problems and majorization. European Journal of Operational Research. ISSN 0377-2217. 158(2), s 434- 443
- Dahl, Geir; Foldnes, Njål & Gouveia, Luis (2004). A note on hop-constrained walk polytopes. Operations Research Letters. ISSN 0167-6377. 32, s 345- 349
- Dahl, Geir & Johannessen, B (2004). The 2-path network problem. Networks. ISSN 0028-3045. 43, s 190- 199
- Brualdi, Richard A. & Dahl, Geir (2003). Majorization-Constrained Doubly Stochastic Matrices. Linear Algebra and its Applications. ISSN 0024-3795. 361, s 75- 97
- Dahl, Geir (2003). A note on linear discrepancy. The Electronic Journal of Linear Algebra. ISSN 1081-3810. 10
- Dahl, Geir (2003). Matrices of zeros and ones with given line sums and a zero block. Linear Algebra and its Applications. ISSN 0024-3795. 371, s 191- 207
- Dahl, Geir (2003). The doubly graded matrix cone and Ferrers matrices. Linear Algebra and its Applications. ISSN 0024-3795. 368, s 171- 190
- Dahl, Geir & Foldnes, Njål (2003). Complete description of a class of knapsack polytopes. Operations Research Letters. ISSN 0167-6377. 31, s 335- 340
- Flatberg, Truls & Dahl, Geir (2003). Optimization and reconstruction of hv-convex (0,1)-matrices. Electronic Notes in Discrete Mathematics. ISSN 1571-0653. 12
- Dahl, Geir; Storvik, Geir Olve & Fadnes, Alice (2002). Large-scale integer programs in image analysis. Operations Research. ISSN 0030-364X. 50(3), s 490- 500
- Dahl, Geir (2001). Principal majorization ideals and optimization. Linear Algebra and its Applications. ISSN 0024-3795. 331, s 113- 130
- Dahl, Geir (2000). A note on diagonally dominant matrices. Linear Algebra and its Applications. ISSN 0024-3795. 317, s 217- 224
- Dahl, Geir & Realfsen, Bjørnar (2000). The cardinality-constrained shortest path problem in 2-graphs. Networks. ISSN 0028-3045. 36(1), s 1- 8
- Storvik, Geir Olve & Dahl, Geir (2000). Lagrangian based methods for finding MAP solutions for MRF models. IEEE Transactions on Image Processing. ISSN 1057-7149. 9(3), s 469- 479
- Dahl, Geir (1999). Majorization polytopes. Linear Algebra and its Applications. ISSN 0024-3795. 297, s 157- 175
- Dahl, Geir (1999). Matrix majorization. Linear Algebra and its Applications. ISSN 0024-3795. 288, s 53- 73
- Dahl, Geir (1999). Notes on polyhedra associated with hop-constrained paths. Operations Research Letters. ISSN 0167-6377. 25, s 97- 101
- Dahl, Geir (1999). Stable set polytopes for a class of circulant graphs. SIAM Journal on Optimization. ISSN 1052-6234. 9(2), s 493- 503
- Dahl, Geir; Martin, Alexander & Stoer, Mechthild (1999). Routing through virtual paths in layered telecommunication networks. Operations Research. ISSN 0030-364X. 47(5), s 693- 702
- Dahl, Geir (1998). Majorization, polyhedra and statistical testing problems. Linear Algebra and its Applications. ISSN 0024-3795. 272, s 205- 225
- Dahl, Geir (1998). Polytopes relates to the l_infty distance between vectors. Operations Research Letters. ISSN 0167-6377. 22, s 49- 54
- Dahl, Geir (1998). The 2-hop spanning tree problem. Operations Research Letters. ISSN 0167-6377. 23, s 21- 26
- Dahl, Geir & Margot, Francois (1998). Weak k-majorization and polyhedra. Mathematical programming. ISSN 0025-5610. 81(1), s 37- 53
- Dahl, Geir & Stoer, Mechthild (1998). A cutting plane for the multicommodity survivable network design problem. INFORMS journal on computing. ISSN 1091-9856. 10(1)
- Dahl, Geir & Holm, Sverre (1997). Properties of the beampattern of weight- and layout-optimized sparse arrays. IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control. ISSN 0885-3010. 44(5), s 983- 982
- 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.
- Dahl, Geir & Brualdi, Richard A. (2003). Matrices of zeros and ones and a zero block.
- Dahl, Geir & Flatberg, Truls (2003). Reconstructing (0,1)-matrices using Lagrangian decomposition.
- Dahl, Geir & Flatberg, Truls (2003). Reconstructing hv-convex (0,1)-matrices by optimization methods.
- Dahl, Geir & Foldnes, Njål (2003). A randomized algorithm for the multiple knapsack problem with assignment restrictions.
- Dahl, Geir & Foldnes, Njål (2003). On hop-constrained walk polytopes.
- Flatberg, Truls & Dahl, Geir (2003). Optimization and reconstruction of hv-convex (0,1)-matrices.
- Dahl, Geir (2002). Majorization and optimization.
- Dahl, Geir (2002). Principal majorization ideal and optimization.
- Dahl, Geir & Flatberg, Truls (2002). Discrete tomography and optimization.
- Dahl, Geir & Flatberg, Truls (2002). Some partitioning problems and majorization.
- Dahl, Geir & Foldnes, Njål (2002). Complexity of certain multiple knapsack problems.
- Dahl, Geir & Foldnes, Njål (2002). Polyhedral Properties of certain 0/1 Knapsack Polytopes.
- Brualdi, Richard A. & Dahl, Geir (2001). Majorization-Constrained Doubly Stochastic Matrices.
- Dahl, Geir (2001). Dobbeltstokastiske matriser, polytoper og majorisering.
- Dahl, Geir (2001). Grafteori og optimering - en kort innføring.
- Dahl, Geir (2001). Integer programs in image analysis.
- Dahl, Geir (2001). The 2-path network design problem and majorization.
- Dahl, Geir & Gouveia, Luis (2001). Generalizing cut inequalities for hop-constrained network design problem.
- Flatberg, Truls & Dahl, Geir (2001). Some partitioning problems involving school classes.
- Dahl, Geir (2000). An introduction to convexity.
- Dahl, Geir (2000). Moderne optimering - mer enn å derivere !!.
- Dahl, Geir (2000). Verdens beste håndball-lag?.
- Dahl, Geir & Johannessen, Bjarne (2000). The 2-path network design problem.
- Dahl, Geir; Storvik, Geir Olve & Fadnes, Alice (1999). Large-scale integer programs in image analysis.
- Dahl, Geir; Storvik, Geir Olve & Fadnes, Alice (1999). Large-scale integer programs in image analysis.
- Løkketangen, Arne; Jörnsten, Kurt; Dahl, Geir & Guangzhong, Liu (1998). A Tabu Search approach to the channel minimization problem.