6 found
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  1.  36
    Universal algebra.Karl Meinke & John V. Tucker - 1992 - Journal of Symbolic Logic 38 (4):1--189.
  2.  53
    Computable and continuous partial homomorphisms on metric partial algebras.Viggo Stoltenberg-Hansen & John V. Tucker - 2003 - Bulletin of Symbolic Logic 9 (3):299-334.
    We analyse the connection between the computability and continuity of functions in the case of homomorphisms between topological algebraic structures. Inspired by the Pour-El and Richards equivalence theorem between computability and boundedness for closed linear operators on Banach spaces, we study the rather general situation of partial homomorphisms between metric partial universal algebras. First, we develop a set of basic notions and results that reveal some of the delicate algebraic, topological and effective properties of partial algebras. Our main computability concepts (...)
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  3.  8
    Logical Models of Mathematical Texts: The Case of Conventions for Division by Zero.Jan A. Bergstra & John V. Tucker - forthcoming - Journal of Logic, Language and Information:1-22.
    Arithmetical texts involving division are governed by conventions that avoid the risk of problems to do with division by zero (DbZ). A model for elementary arithmetic texts is given, and with the help of many examples and counter examples a partial description of what may be called traditional conventions on DbZ is explored. We introduce the informal notions of legal and illegal texts to analyse these conventions. First, we show that the legality of a text is algorithmically undecidable. As a (...)
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  4.  39
    Physical Oracles: The Turing Machine and the Wheatstone Bridge.Edwin J. Beggs, José Félix Costa & John V. Tucker - 2010 - Studia Logica 95 (1-2):279-300.
    Earlier, we have studied computations possible by physical systems and by algorithms combined with physical systems. In particular, we have analysed the idea of using an experiment as an oracle to an abstract computational device, such as the Turing machine. The theory of composite machines of this kind can be used to understand (a) a Turing machine receiving extra computational power from a physical process, or (b) an experimenter modelled as a Turing machine performing a test of a known physical (...)
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  5.  28
    Three forms of physical measurement and their computability.Edwin Beggs, José Félix Costa & John V. Tucker - 2014 - Review of Symbolic Logic 7 (4):618-646.
    We have begun a theory of measurement in which an experimenter and his or her experimental procedure are modeled by algorithms that interact with physical equipment through a simple abstract interface. The theory is based upon using models of physical equipment as oracles to Turing machines. This allows us to investigate the computability and computational complexity of measurement processes. We examine eight different experiments that make measurements and, by introducing the idea of an observable indicator, we identify three distinct forms (...)
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  6.  25
    Stability of representations of effective partial algebras.Jens Blanck, Viggo Stoltenberg-Hansen & John V. Tucker - 2011 - Mathematical Logic Quarterly 57 (2):217-231.
    An algebra is effective if its operations are computable under some numbering. When are two numberings of an effective partial algebra equivalent? For example, the computable real numbers form an effective field and two effective numberings of the field of computable reals are equivalent if the limit operator is assumed to be computable in the numberings . To answer the question for effective algebras in general, we give a general method based on an algebraic analysis of approximations by elements of (...)
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