Results 111 to 120 of about 5,823 (137)

The intersection of nonstandard models of arithmetic

Journal of Symbolic Logic, 1972
If two nonstandard models of complete arithmetic are elementarily embedded in a third, then their intersection may be considerably smaller than either of them; indeed, the intersection may be only the standard model. For example, if D and E are nonprincipal ultrafilters on ω, then the nonstandard models D-prod and E-prod (where is the standard model)
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Recursively saturated nonstandard models of arithmetic; addendum

Journal of Symbolic Logic, 1982
These additions to the author's paper [ibid. 46, 259-286 (1981; Zbl 0501.03044)] rely mainly on unpublished work of several authors. In particular, an argument (due to R. Solovay) is outlined that there are no short cofinally resplendent models.
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On external Scott algebras in nonstandard models of Peano arithmetic

Journal of Symbolic Logic, 1996
AbstractWe prove that a necessary and sufficient condition for a countable set of sets of integers to be equal to the algebra of all sets of integers definable in a nonstandard elementary extension of ω by a formula of the PA language which may include the standardness predicate but does not contain nonstandard parameters, is as follows: is closed ...
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Nonstandard Models for a Fragment of the Arithmetic and Their Decision Problem

Mathematical Logic Quarterly, 1987
In my thesis [see Bonner Math. Schriften 61 (1973; Zbl 0279.02039)] I have introduced the theory of Very Weak Induction for open formulae VWIO, which differs from WIO (AIO) studied by \textit{J. C. Shepherdson} [Bull. Acad. Pol. Sci., Ser. Sci. Math. Astron. Phys.
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The Fine Structure Theory of Nonstandard Models of Peano Arithmetic

This paper delves into the fine structure theory of nonstandard models of Peano Arithmetic (PA). Nonstandard models provide a rich landscape for exploring foundational issues in arithmetic, extending beyond the intuitive standard model of natural numbers.
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On the nonstandard finite difference method for reaction–diffusion models

Chaos, Solitons and Fractals, 2023
Syed Ahmed Pasha, Yasir Nawaz, Muhammad Shoaib Arif   +2 more
exaly  

Construction of nonstandard finite difference schemes for the SI and SIR epidemic models of fractional order

Mathematics and Computers in Simulation, 2016
Abraham Jose Arenas Tawil, Gilberto C González-Parra   +1 more
exaly  

Nonstandard heavy mesons and baryons: Experimental evidence

Reviews of Modern Physics, 2018
Tomasz Skwarnicki
exaly  

A functional interpretation for nonstandard arithmetic

Annals of Pure and Applied Logic, 2012
Benno van den Berg
exaly  

Positive and elementary stable nonstandard numerical methods with applications to predator–prey models

Journal of Computational and Applied Mathematics, 2006
Hristo V Kojouharov
exaly