The equivalence problem for a group G is the problem of deciding which equations hold in G. It is known that for finite nilpotent groups and certain other solvable groups, the equivalence problem has polynomial-time complexity. We prove that the equivalence problem for a finite nonsolvable group G is co-NP-complete by reducing the k-coloring problem for graphs to the equivalence problem, where ...

In this paper, we introduce and study fuzzy variational-like inclusion, fuzzy resolvent equation and $H(cdot,cdot)$-$phi$-$eta$-accretive operator in real  uniformly smooth Banach spaces. It is established that fuzzy variational-like inclusion is equivalent to a fixed point problem as well as to a fuzzy resolvent equation. This equivalence is used to define an iterative algorithm for solving fu...

We prove that observational equivalence of IA3 + Y0 (3rdorder Idealized Algol with 0th-order recursion) is equivalent to the DPDA Equivalence Problem, and hence decidable. This completes the classification of decidable fragments of Idealized Algol. We also prove that observational approximation of IA1 + Y0 is undecidable by reducing the DPDA Containment Problem to it.

recently, lotfi et al. [10] established an equivalence model between the output-oriented dual ccr model and multiple objective linear programming (molp) and used an interactive method for finding target unit on efficiency frontier such that the decision maker preferences can be taken into account. however their method is not applicable for situations in which some outputs are undesirable and ne...

Formal methods have proved their usefulness for analyzing the security of protocols. Most existingresults focus on trace properties like secrecy or authentication. There are however several securityproperties, which cannot be defined (or cannot be naturally defined) as trace properties and requirea notion of behavioural equivalence. Typical examples are anonymity, privacy related pr...

Identifying keyword associations from text and search sources is often used to facilitate many tasks such as understanding relationships among concepts, extracting relevant documents, matching advertisements to web pages, expanding user queries, etc. However, these keyword associations change as the underlying content changes with time. Two keywords that are associated with each other during on...

A fundamental fact for the algebraic theory of constraint satisfaction problems (CSPs) over a fixed template is that pp-interpretations between at most countable ω-categorical relational structures have two algebraic counterparts for their polymorphism clones: a semantic one via the standard algebraic operators H, S, P, and a syntactic one via clone homomorphisms (capturing identities). We prov...

Questions whether or not two grammars belonging to a family of grammars generate the same language have extensively been studied in the literature. These problems are called equivalence problems and if there exists an algorithm which for each pair of grammars of this family gives an answer to this question then the equivalence problem for this family of grammars is said to be decidable. Otherwi...