MPI-I-98-2-013
Rigid reachability
Ganzinger, Harald and Jacquemard, Florent and Veanes, Margus
September 1998, 24 pages.
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Status: available - back from printing
We show that rigid reachability, the non-symmetric form of rigid
E-unification, is undecidable already in the case of a single
constraint. From this we infer the undecidability of a new
rather restricted kind of second-order unification.
We also show that certain decidable subclasses of the problem
which are PTIME-complete in the equational case
become EXPTIME-complete when symmetry is absent.
By applying automata-theoretic methods,
simultaneous monadic rigid reachability with ground rules
is shown to be in EXPTIME.
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URL to this document: https://domino.mpi-inf.mpg.de/internet/reports.nsf/NumberView/1998-2-013
BibTeX
@TECHREPORT{GanzingerJacquemardVeanes98,
AUTHOR = {Ganzinger, Harald and Jacquemard, Florent and Veanes, Margus},
TITLE = {Rigid reachability},
TYPE = {Research Report},
INSTITUTION = {Max-Planck-Institut f{\"u}r Informatik},
ADDRESS = {Im Stadtwald, D-66123 Saarbr{\"u}cken, Germany},
NUMBER = {MPI-I-98-2-013},
MONTH = {September},
YEAR = {1998},
ISSN = {0946-011X},
}