TY - GEN
T1 - Focussing, MALL and the Polynomial Hierarchy
AU - Das, Anupam
PY - 2018/6/30
Y1 - 2018/6/30
N2 - We investigate how to extract alternating time bounds from ‘focussed’ proofs, treating non-invertible rule phases as nondeterministic computation and invertible rule phases as co-nondeterministic computation. We refine the usual presentation of focussing to account for deterministic computations in proof search, which correspond to invertible rules that do not branch, more faithfully associating phases of focussed proof search to their alternating time complexity. As our main result, we give a focussed system for MALLw (MALL with weakening) with encodings to and from true quantified Boolean formulas (QBFs): in one direction we encode QBF satisfiability and in the other we encode focussed proof search. Moreover we show that the composition of the two encodings preserves quantifier alternation, yielding natural fragments of MALLw complete for each level of the polynomial hierarchy. This refines the well-known result that MALLw is PSPACE-complete.
AB - We investigate how to extract alternating time bounds from ‘focussed’ proofs, treating non-invertible rule phases as nondeterministic computation and invertible rule phases as co-nondeterministic computation. We refine the usual presentation of focussing to account for deterministic computations in proof search, which correspond to invertible rules that do not branch, more faithfully associating phases of focussed proof search to their alternating time complexity. As our main result, we give a focussed system for MALLw (MALL with weakening) with encodings to and from true quantified Boolean formulas (QBFs): in one direction we encode QBF satisfiability and in the other we encode focussed proof search. Moreover we show that the composition of the two encodings preserves quantifier alternation, yielding natural fragments of MALLw complete for each level of the polynomial hierarchy. This refines the well-known result that MALLw is PSPACE-complete.
UR - http://www.scopus.com/inward/record.url?scp=85049956770&partnerID=8YFLogxK
U2 - 10.1007/978-3-319-94205-6_45
DO - 10.1007/978-3-319-94205-6_45
M3 - Conference contribution
AN - SCOPUS:85049956770
SN - 9783319942049
T3 - Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)
SP - 689
EP - 705
BT - Automated Reasoning:
A2 - Sebastiani, Roberto
A2 - Galmiche, Didier
A2 - Schulz, Stephan
PB - Springer
T2 - 9th International Joint Conference on Automated Reasoning, IJCAR 2018 Held as Part of the Federated Logic Conference, FloC 2018
Y2 - 14 July 2018 through 17 July 2018
ER -