Infinite Combinatorial Issues Raised by Lifting Problems in Universal Algebra

Infinite Combinatorial Issues Raised by Lifting Problems in Universal Algebra

The critical point between varieties A and B of algebras is defined as the least cardinality of the semilattice of compact congruences of a member of A but of no member of B, if it exists. The study of critical points gives rise to a whole array of problems, often involving lifting problems of either diagrams or objects, with respect to functors. These, in turn, involve problems that belong to ...

Complexity of Some Problems in Universal Algebra

In this paper we consider the complexity of several problems involving finite algebraic structures. Given finite universal algebras A and B, these problems ask: (1) Do A and B satisfy precisely the same identities? (2) Do they satisfy the same quasi-identities? and (3) Do A and B have the same set of term operations? In addition to the general case in which we allow arbitrary (finite) algebras,...

Statistical issues raised by the

New security issues raised by open cards

The methods, languages and tools for developing a smart card system share some characteristics with those of the embedded domain. Until recently, smart card programs were written in hand coded native assembly language. All programs (drivers, operating system, libraries, applications) were developed as a monolithic piece of code burned in the smart card ROM. Therefore, not only are traditional c...

Economic Issues Raised by Treatment of Takings