Abstract:
We introduce and study some natural operations on a structure of finite labeled forests, which is crucial in extending the difference hierarchy to the case of partitions. It is shown that the corresponding quotient algebra modulo the so-called h-equivalence is the simplest non-trivial semilattice with discrete closures. The algebra is also characterized as a free algebra in some quasivariety. Part of the results is generalized to countable labeled forests with finite chains.
Citation:
V. L. Selivanov, “The quotient algebra of labeled forests modulo h-equivalence”, Algebra Logika, 46:2 (2007), 217–243; Algebra and Logic, 46:2 (2007), 120–133
Victor Selivanov, Trends in Logic, 53, Well-Quasi Orders in Computation, Logic, Language and Reasoning, 2020, 271
Selivanov V., “Towards a Descriptive Theory of Cb(0)-Spaces”, Math. Struct. Comput. Sci., 27:8 (2017), 1553–1580
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Victor Selivanov, Lecture Notes in Computer Science, 6735, Models of Computation in Context, 2011, 260
Selivanov V.L., “On the Wadge reducibility of k-partitions”, J. Log. Algebr. Program., 79:1 (2010), 92–102
A. V. Zhukov, O. V. Kudinov, V. L. Selivanov, “Definability of closure operations in the h-quasiorder of labeled forests”, Algebra and Logic, 49:2 (2010), 120–129
Kudinov O.V., Selivanov V.L., Zhukov A.V., “Definability in the h-quasiorder of labeled forests”, Ann. Pure Appl. Logic, 159:3 (2009), 318–332
Selivanov V.L., “Undecidability of some structures related to computation theory”, J. Logic Comput., 19:1 (2009), 177–197
Selivanov V.L., “Fine hierarchies and m-reducibilities in theoretical computer science”, Theoret. Comput. Sci., 405:1-2 (2008), 116–163
Victor Selivanov, “On the Difference Hierarchy in Countably Based T0-Spaces”, Electronic Notes in Theoretical Computer Science, 221 (2008), 257