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This paper discusses the semantics of Codd's relational model of data, considered as being time-independent properties of the relations describing the data. The paper emphasizes those properties which are expressible in terms of the relations present in the data base, as opposed to the properties which relate the data base to the outside world. Among the semantic properties being discussed are the...
The paper attempts (i) to present descriptional complexity as an identifiable part of the theory of complexity incorporating many diverse areas of research, (ii) to formulate basic problems and to survey some results (especially those concerning languages) in descriptional complexity, (iii) to discuss relation between descriptional and computational complexity.
The paper reviews the solvability resp. unsolvability of decision problems for the relations represented by deterministic and nondeterministic multi-tape automata with or without endmarker on the one hand and the solvability resp. unsolvability of decision problems for the languages defined by the same types of automata on the other hand. The first section presents results on the inclusions between...
The order-theoretic enrichment of the algebraic approach to theoretical computer science, and to the theory of programming in particular, can be accomplished rather directly and elegantly, and appears to have a wide range of applications. This paper presents mathematical fundamentals of order-algebraic semantics. The principal new results concern free continuous algebraic theories and minimal conditions...
In the area of semantics of programming languages the problem of calculating the termination domain (the set of inputs for which a program terminates) is considered: For simple non-nested loop-programs compile-time testable conditions are given such that the resp. programs are total (terminate for all inputs). Auxiliary tool is a global (=mathematical) semantics for infinite loop-programs whose properties...
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