Decidability and structure

the underlying structure of language proficiency and the proficiency level

هدف از انجام این تخقیق بررسی رابطه احتمالی بین سطح مهارت زبان خارجی (foreign language proficiency) و ساختار مهارت زبان خارجی بود. تعداد 314 زبان آموز مونث و مذکر که عمدتا دانشجویان رشته های زبان انگلیسی در سطوح کارشناسی و کارشناسی ارشد بودند در این تحقیق شرکت کردند. از لحاظ سطح مهارت زبان خارجی شرکت کنندگان بسیار با هم متفاوت بودند، (75 نفر سطح پیشرفته، 113 نفر سطح متوسط، 126 سطح مقدماتی). کلا ...

Decidability and Tameness in the Theory of Finite Semigroups

Topological Semantics and Decidability

It is well-known that the basic modal logic of all topological spaces is S4. However, the structure of basic modal and hybrid logics of classes of spaces satisfying various separation axioms was until present unclear. We prove that modal logics of T0, T1 and T2 topological spaces coincide and are S4. We also examine basic hybrid logics of these classes and prove their decidability; as part of t...

Complexity, decidability and completeness

We give resource bounded versions of the Completeness Theorem for propositional and predicate logic. For example, it is well known that every computable consistent propositional theory has a computable complete consistent extension. We show that, when length is measured relative to the binary representation of natural numbers and formulas, every polynomial time decidable propositional theory ha...

Tetris and decidability

We consider a variant of TETRIS where the sequence of pieces (together with their orientation and horizontal position, which cannot be changed anymore) is generated by a finite state automaton. We show that it is undecidable, given such an automaton, and starting from an empty game board, whether one of the generated sequences leaves an empty game board. This is contrasted with more common situ...