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We formalize a transfinite Phi process that treats all possibility embeddings as operators on structured state spaces including complete lattices, Banach and Hilbert spaces, and orthomodular lattices. We prove a determinization lemma…

Functional Analysis · Mathematics 2025-08-15 Bugra Kilictas , Faruk Alpay

We show that the theory $I\Sigma_1$ of $\Sigma_1$-induction proves the following statement: For all $n\geq 2$, the uniform $\Sigma_1$-reflection principle over the theory $I\Sigma_n$ is equivalent to the totality of the function…

Logic · Mathematics 2015-12-17 Anton Freund

In the context of the correspondence between real functions on the unit circle and inner analytic functions within the open unit disk, that was presented in previous papers, we show that the constructions used to establish that…

Complex Variables · Mathematics 2019-02-19 Jorge L. deLyra

Schmerl and Beklemishev's work on iterated reflection achieves two aims: It introduces the important notion of $\Pi^0_1$-ordinal, characterizing the $\Pi^0_1$-theorems of a theory in terms of transfinite iterations of consistency; and it…

Logic · Mathematics 2018-07-17 Anton Freund

By iterative techniques,we present two fixed point theorems, whose modular formulations are relatively close to the Banach's fixed point theorem in the normed spaces.The first result concerns the fixed point of the strongly contraction…

Functional Analysis · Mathematics 2016-09-07 Hanebaly Elaidi

In this paper we show how a second order scalar uniformly elliptic equation on divergence form with measurable coefficients and Dirichlet boundary conditions can be transformed into a first order elliptic system with half-Dirichlet boundary…

Analysis of PDEs · Mathematics 2021-04-27 Erik Duse

Due to the fundamental works of T. Ando, W. Szyma\'nski, F. H. Szafraniec, and many others it is well known that sesquilinear forms play an important role in dilation theory. The crucial fact is that every positive definite operator…

Functional Analysis · Mathematics 2014-11-27 Tamás Titkos

In recent work of Kennard, Khalili Samani, and the last author, they generalize the Half-Maximal Symmetry Rank result of Wilking for torus actions on positively curved manifolds to $\mathbb{Z}_2$-tori with a fixed point. They show that if…

Differential Geometry · Mathematics 2024-11-04 Austin Bosgraaf , Christine Escher , Catherine Searle

We show that the two-point function of protected bi-scalar operators in ${\cal N}=4$ SYM evaluated in dimensional regularization exhibits a uniform degree of transcendentality up to three-loop order. We conjecture that this property holds…

High Energy Physics - Theory · Physics 2023-06-13 Marco S. Bianchi

Inductive and coinductive specifications are widely used in formalizing computational systems. Such specifications have a natural rendition in logics that support fixed-point definitions. Another useful formalization device is that of…

Logic in Computer Science · Computer Science 2012-04-30 David Baelde , Gopalan Nadathur

In this survey article (which hitherto is an ongoing work-in-progress) we present the formulation of the induction and coinduction principles using the language and conventions of each of order theory, set theory, programming languages'…

Logic in Computer Science · Computer Science 2019-03-13 Moez A. AbdelGawad

This paper investigates asymptotic fixed point results for nonlinear contractions, with emphasis on Kirk-type theorems and their generalizations. A central difficulty in the literature has been the requirement that the mapping possesses a…

Functional Analysis · Mathematics 2025-07-09 Hassan Khandani

We present an extension of the second-order logic AF2 with iso-style inductive and coinductive definitions specifically designed to extract programs from proofs a la Krivine-Parigot by means of primitive (co)recursion principles. Our logic…

Logic in Computer Science · Computer Science 2012-03-29 Favio Ezequiel Miranda-Perea , Lourdes del Carmen González-Huesca

We introduce a concept of a quasi proximate order which is a generalization of a proximate order and allows us to study efficiently analytic functions whose order and lower order of growth are different. We prove an existence theorem of a…

Complex Variables · Mathematics 2020-07-17 Igor Chyzhykov , Petro Filevych , Jouni Rättyä

Here we develop a regularity theory for a polyconvex functional in $2\times2-$dimensional compressible finite elasticity. In particular, we consider energy minimizers/stationary points of the functional…

Analysis of PDEs · Mathematics 2022-05-19 Marcel Dengler

In this paper we give an ordinal analysis of the theory of second order arithmetic. We do this by working with proof trees -- that is, "deductions" which may not be well-founded. Working in a suitable theory, we are able to represent…

Logic · Mathematics 2024-03-27 Henry Towsner

In this paper, we develop an Isabelle/HOL library of order-theoretic fixed-point theorems. We keep our formalization as general as possible: we reprove several well-known results about complete orders, often with only antisymmetry or…

Logic in Computer Science · Computer Science 2023-06-22 Jérémy Dubut , Akihisa Yamada

We give necessary and sufficient conditions for a function in a naturally appearing functional space to be a fixed point of the Ruelle-Thurston operator associated to a rational function, see Lemma 2.1. The proof uses essentially a recent…

Dynamical Systems · Mathematics 2020-07-23 Genadi Levin

It is shown that there exists a normal uniform algebra, on a compact metrizable space, that fails to be strongly regular at some peak point. This answers a 31-year-old question of Joel Feinstein. Our example is R(K) for a certain compact…

Complex Variables · Mathematics 2024-10-09 Alexander J. Izzo

In this paper, we study the existence of fixed points for mappings defined on complete metric space (X, d) satisfying a general contractive inequality of integral type depended on another function. This conditions is analogous of Banach…

Functional Analysis · Mathematics 2009-03-10 S. Moradi , A. Beiranvand