Integer Programming and Incidence Treedepth

Autor: Sebastian Ordyniak, Michał Pilipczuk, Dušan Knop, Marcin Wrochna, Robert Ganian, Eduard Eiben
Jazyk: angličtina
Rok vydání: 2020
Předmět:
Zdroj: Integer Programming and Combinatorial Optimization-20th International Conference, IPCO 2019, Ann Arbor, MI, USA, May 22-24, 2019, Proceedings
Lecture Notes in Computer Science
Lecture Notes in Computer Science-Integer Programming and Combinatorial Optimization
Integer Programming and Combinatorial Optimization ISBN: 9783030179526
IPCO
ISSN: 0302-9743
1611-3349
Popis: Recently a strong connection has been shown between the tractability of integer programming (IP) with bounded coefficients on the one side and the structure of its constraint matrix on the other side. To that end, integer linear programming is fixed-parameter tractable with respect to the primal (or dual) treedepth of the Gaifman graph of its constraint matrix and the largest coefficient (in absolute value). Motivated by this, Kouteck\'y, Levin, and Onn [ICALP 2018] asked whether it is possible to extend these result to a more broader class of integer linear programs. More formally, is integer linear programming fixed-parameter tractable with respect to the incidence treedepth of its constraint matrix and the largest coefficient (in absolute value)? We answer this question in negative. In particular, we prove that deciding the feasibility of a system in the standard form, ${A\mathbf{x} = \mathbf{b}}, {\mathbf{l} \le \mathbf{x} \le \mathbf{u}}$, is $\mathsf{NP}$-hard even when the absolute value of any coefficient in $A$ is 1 and the incidence treedepth of $A$ is 5. Consequently, it is not possible to decide feasibility in polynomial time even if both the assumed parameters are constant, unless $\mathsf{P}=\mathsf{NP}$. Moreover, we complement this intractability result by showing tractability for natural and only slightly more restrictive settings, namely: (1) treedepth with an additional bound on either the maximum arity of constraints or the maximum number of occurrences of variables and (2) the vertex cover number.
Comment: 11 pages, 1 figure. This is an extended version of an article that appeared at IPCO 2019
Databáze: OpenAIRE