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We apply an inductive argument to three theorems of Cantor on (1) the uncountability of infinite binary sequences, (2) the uncountability of real numbers, and (3) the non-equinumerosity of sets with their powersets. This technique proves…

Logic · Mathematics 2025-10-20 Saeed Salehi

We construct uncountably categorical 3-nilpotent groups of exponent p > 3. They are not one-based and do not allow the interpretation of an infinite field. Therefore they are counterexamples to Zilbers Conjecture. First 2-nilpotent new…

Logic · Mathematics 2022-01-10 Andreas Baudisch

We introduce a construction that turns a category of pure state spaces and operators into a category of observable algebras and superoperators. For example, it turns the category of finite-dimensional Hilbert spaces into the category of…

Quantum Physics · Physics 2014-09-17 Bob Coecke , Chris Heunen , Aleks Kissinger

Answering a question raised by V. V. Tkachuk, we present several examples of $\sigma$-compact spaces, some only consistent and some in ZFC, that are not countably tight but in which the closure of any discrete subset is countably tight. In…

General Topology · Mathematics 2024-11-08 István Juhász , Jan van Mill

We study the relative position of four subspaces in a Hilbert space. For any positive integer n, we give an example of exotic indecomposable system of four subspaces in a Hilbert space whose defect is (2n+1)/3. By an exotic system, we mean…

Functional Analysis · Mathematics 2007-05-23 Masatoshi Enomoto , Yasuo Watatani

Usual math sets have special types: countable, compact, open, occasionally Borel, rarely projective, etc. Each such set is described by a single Set Theory formula with parameters unrelated to other formulas. Exotic expressions involving…

Logic in Computer Science · Computer Science 2026-04-01 Leonid A. Levin

In the paper we study properties of the set of critical points for self-similar sets. We introduce simple condition that implies at most countably many critical values and we construct a self-similar set with uncountable set of critical…

Metric Geometry · Mathematics 2011-09-12 Dusan Pokorny

We introduce algebraic sets in the products of complex projective spaces for the mixed states in multipartite quantum systems as their invariants under local unitary operations. The algebraic sets have to be the union of the linear…

Quantum Physics · Physics 2007-05-23 Hao Chen

In set theory without the Axiom of Choice, we study the possible placement of Erdos-Dushnik-Miller theorem restricted to an uncountable set of vertices in the hierarchy of weak choice forms. We also answer a part of a question raised by…

Logic · Mathematics 2023-09-13 Amitayu Banerjee , Alexa Gopaulsingh

We use classes of Hilbert lattice equations for an alternative representation of Hilbert lattices and Hilbert spaces of arbitrary quantum systems that might enable a direct introduction of the states of the systems into quantum computers.…

Quantum Physics · Physics 2008-12-17 Mladen Pavicic , Norman D. Megill

It is studied a connection between the separability and the countable chain condition of spaces with the $L$-property (a topological space $X$ has the $L$-property if for every topological space $Y$, separately continuous function…

General Topology · Mathematics 2015-12-29 V. V. Mykhaylyuk

As a toy model for the implementation of the diffeomorphism constraint, the interpretation of the resulting states, and the treatment of ordering ambiguities in loop quantum gravity, we consider the Hilbert space of spatially diffeomorphism…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Hanno Sahlmann

Using an iterative tree construction we show that for simple computable subsets of the Cantor space Hausdorff, constructive and computable dimensions might be incomputable.

Logic in Computer Science · Computer Science 2024-05-24 Ludwig Staiger

We discuss the question of entanglement versus separability of pure quantum states in direct product Hilbert spaces and the relevance of this issue to physics. Different types of separability may be possible, depending on the particular…

Quantum Physics · Physics 2009-11-07 Jon Eakins , George Jaroszkiewicz

In this paper we prove three theorems about the theory of Borel sets in models of ZF without any form of the axiom of choice. We prove that if B is a G-delta-sigma set, then either B is countable or B contains a perfect subset. Second, we…

Logic · Mathematics 2008-06-13 Arnold W. Miller

We study the possible structures which can be carried by sets which have no countable subset, but which fail to be `surjectively Dedekind finite', in two possible senses, that there is a surjection to $\omega$, or alternatively, that there…

Logic · Mathematics 2025-09-17 Supakun Panasawatwong , J K Truss

In this paper we introduce and study some Hilbert-type operators acting from the function spaces into the sequence spaces. We give some sufficient and necessary conditions for the boundedness and compactness of these Hilbert-type operators.…

Functional Analysis · Mathematics 2023-12-27 Jianjun Jin

We consider the compact spaces sigma_n(I) of subsets of an uncountable set I of cardinality at most n and their countable products. We give a complete classification of their Banach spaces of continuous functions and a partial topological…

General Topology · Mathematics 2009-03-03 Antonio Avilés

Mutually unbiased bases in Hilbert spaces of finite dimensions are closely related to the quantal notion of complementarity. An alternative proof of existence of a maximal collection of N+1 mutually unbiased bases in Hilbert spaces of prime…

Quantum Physics · Physics 2007-12-10 P. Sulc , J. Tolar

It is shown that quantized dynamical system with second class constraints has infinite dimensional Hilbert space.

Mathematical Physics · Physics 2013-04-10 M. N. Stoilov