Abstract
This paper investigates the computational complexity of deciding if a given finite algebra is an expansion of a semilattice. In general this problem is known to be EXP-TIME complete, and we show that even for idempotent algebras, this problem remains hard. This result is in contrast to a series of results that show that similar decision problems turn out to be tractable.
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Acknowledgments
The first author was supported by the National Science Foundation under grant No. 1500235 and the third author was supported by a grant from the Natural Sciences and Engineering Research Council of Canada.
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Freese, R., Nation, J.B. & Valeriote, M. Testing for a Semilattice Term. Order 36, 65–76 (2019). https://doi.org/10.1007/s11083-018-9455-6
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DOI: https://doi.org/10.1007/s11083-018-9455-6