Rights statement: This is the author’s version of a work that was accepted for publication in Operations Research Letters. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Operations Research Letters, 49, 4, 2021 DOI: 10.1016/j.orl.2021.05.011
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Research output: Contribution to Journal/Magazine › Journal article › peer-review
Research output: Contribution to Journal/Magazine › Journal article › peer-review
}
TY - JOUR
T1 - On the complexity of surrogate and group relaxation for integer linear programs
AU - Dokka, Trivikram
AU - Letchford, Adam
AU - Mansoor, Hasan
N1 - This is the author’s version of a work that was accepted for publication in Operations Research Letters. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Operations Research Letters, vol. 49, issue 4, 2021 DOI:10.1016/j.orl.2021.05.011
PY - 2021/7/31
Y1 - 2021/7/31
N2 - Surrogate and group relaxation have been used to compute bounds for various integer linear programming problems. We prove that (a) when only inequalities are surrogated, the surrogate dual is NP-hard, but solvable in pseudo-polynomial time under certain conditions; (b) when equations are surrogated, the surrogate dual exhibits unusual complexity behaviour; (c) the group relaxation is NP-hard for theinteger and 0-1 knapsack problems, and strongly NP-hard for the set packing problem.
AB - Surrogate and group relaxation have been used to compute bounds for various integer linear programming problems. We prove that (a) when only inequalities are surrogated, the surrogate dual is NP-hard, but solvable in pseudo-polynomial time under certain conditions; (b) when equations are surrogated, the surrogate dual exhibits unusual complexity behaviour; (c) the group relaxation is NP-hard for theinteger and 0-1 knapsack problems, and strongly NP-hard for the set packing problem.
KW - Integer programming
KW - Surrogate relaxation
KW - Group relaxation
U2 - 10.1016/j.orl.2021.05.011
DO - 10.1016/j.orl.2021.05.011
M3 - Journal article
VL - 49
SP - 530
EP - 534
JO - Operations Research Letters
JF - Operations Research Letters
SN - 0167-6377
IS - 4
ER -