On the Complexity of Unification and Disunification in Commutative Idempotent Semigroups

@inproceedings{Hermann1997OnTC,
  title={On the Complexity of Unification and Disunification in Commutative Idempotent Semigroups},
  author={Miki Hermann and Phokion G. Kolaitis},
  booktitle={CP},
  year={1997}
}
We analyze the computational complexity of elementary unification and disunification problems for the equational theory ACI of commutative idempotent semigroups. From earlier work, it was known that the decision problem for elementary ACI-unification is solvable in polynomial time. We show that this problem is inherently sequential by establishing that it is complete for polynomial time (P-complete) via logarithmic-space reductions. We also investigate the decision problem and the counting… 
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Unification Theory

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