Equality languages and fixed point languages

Equality Languages and Fixed Point Languages

This paper considers equality hmguages and fixed-point languages of homomorphisms and deterministic gsm mappings. It provides some basic properties of these classes of languages. Vfe introduce a new subclass of dgsm mappings, the so-called symmetric dgsm mappings. We prove that (unlike for arbitrary dgsm mappings) their fixed-point languages are regular but not effectively obtainable. This resu...

Bounded Fixed-Point Definability and Tabular Recognition of Languages

By relating positive inductive definitions to space-bounded computations of alternating Turing machines, Rounds, Comp. Linguistics 14, 1988, has given uniform grammatical characterizations of the EXPTIME and PTIME languages. But his proof gives fairly poor bounds for language recognition with context-free resp. head grammars. We improve Rounds’ analysis in two respects: first, we introduce a mo...

Title: Equality in Object Oriented Languages Equality in Object Oriented Languages

Traditional programming languages provide a simpliied view of equality. Many programmers have apparently inferred that equality itself is a simple concept | a matter of writing`=' in the right place and leaving the rest to the compiler. Equality tests involve semantic relationships, however, and it follows that a compiler cannot generate correct equality tests for user-deened types. In the soph...

Metacognitive (Rending) Strategies Across Languages and Techniques

Lattices of Theories in Languages without Equality

If S is a semilattice with operators, then there is an implicational theory Q such that the congruence lattice Con(S) is isomorphic to the lattice of all implicational theories containing Q. The author and Kira Adaricheva have shown that lattices of quasi-equational theories are isomorphic to congruence lattices of semilattices with operators [1]. That is, given a quasi-equational theory Q, the...