Zobrazeno 1 - 10
of 134
pro vyhledávání: '"Lubarsky, Robert"'
Autor:
Banakh, Taras1,2 (AUTHOR) t.o.banakh@gmail.com, Lubarsky, Robert S.3 (AUTHOR) Robert.Lubarsky@alum.mit.edu
Publikováno v:
Computability. 2024, Vol. 13 Issue 3/4, p223-236. 14p.
Publikováno v:
Logical Methods in Computer Science, Volume 15, Issue 2 (April 30, 2019) lmcs:3834
We introduce the notion of feedback computable functions from $2^\omega$ to $2^\omega$, extending feedback Turing computation in analogy with the standard notion of computability for functions from $2^\omega$ to $2^\omega$. We then show that the feed
Externí odkaz:
http://arxiv.org/abs/1708.01139
Autor:
Lubarsky, Robert, Richman, Fred
Publikováno v:
Communications in Algebra, 42, No. 4 (2014), pp. 1644-1649
Walker's cancellation theorem says that if B+Z is isomorphic to C+Z in the category of abelian groups, then B is isomorphic to C. We construct an example in a diagram category of abelian groups where the theorem fails. As a consequence, the original
Externí odkaz:
http://arxiv.org/abs/1510.02137
Autor:
Lubarsky, Robert S., Diener, Hannes
Publikováno v:
Journal of Symbolic Logic, 79, No. 3 (2014), pp. 792-813
Varieties of the Fan Theorem have recently been developed in reverse constructive mathematics, corresponding to different continuity principles. They form a natural implicational hierarchy. Some of the implications have been shown to be strict, other
Externí odkaz:
http://arxiv.org/abs/1510.02141
Autor:
Lubarsky, Robert S., Rathjen, Michael
Publikováno v:
Proceedings, Computability in Europe 2013, Lecture Notes in Computer Science #7921 (Bonizzoni, Brattka, and Loewe, eds.), Springer, 2013, pp. 306-315
We develop a realizability model in which the realizers are the reals not just Turing computable in a fixed real but rather the reals in a countable ideal of Turing degrees. This is then applied to prove several separation results involving variants
Externí odkaz:
http://arxiv.org/abs/1510.02147
Autor:
Lubarsky, Robert S., Diener, Hannes
Publikováno v:
Journal of Symbolic Logic, 78, No. 3 (2013), pp. 873-885
BD-N is a weak principle of constructive analysis. Several interesting principles implied by BD-N have already been identified, namely the closure of the anti-Specker spaces under product, the Riemann Permutation Theorem, and the Cauchyness of all pa
Externí odkaz:
http://arxiv.org/abs/1510.02139
Autor:
Lubarsky, Robert
Publikováno v:
Journal of Symbolic Logic, 78, No. 1 (2013), pp. 39-56
We give the natural topological model for the failure of BD-N, and use it to show that the closure of spaces with the anti-Specker property under product does not imply BD-N. Also, the natural topological model for the failure of BD is presented. Fin
Externí odkaz:
http://arxiv.org/abs/1510.00990
Autor:
Lubarsky, Robert
Publikováno v:
Journal of Logic and Analysis, http://logicandanalysis.org/, 2, No. 6 (2010), pp. 1-10
Some models of set theory are given which contain sets that have some of the important characteristics of being geometric, or spatial, yet do not have any points, in various ways. What's geometrical is that there are functions to these spaces defined
Externí odkaz:
http://arxiv.org/abs/1510.00988
Autor:
Lubarsky, Robert, Richman, Fred
Publikováno v:
Transaction of the AMS, 362 (2010), pp. 6619-6632
Let L be the zero set of a nonconstant monic polynomial with complex coefficients. In the context of constructive mathematics without countable choice, it may not be possible to construct an element of L. In this paper we introduce a notion of distan
Externí odkaz:
http://arxiv.org/abs/1510.00732
Autor:
Lubarsky, Robert
Publikováno v:
Annals of Pure and Applied Logic, 163 (2012), pp. 820-830
It was realized early on that topologies can model constructive systems, as the open sets form a Heyting algebra. After the development of forcing, in the form of Boolean-valued models, it became clear that, just as over ZF any Boolean-valued model a
Externí odkaz:
http://arxiv.org/abs/1510.00719