scholarly journals INFINITE COMBINATORICS PLAIN AND SIMPLE

2018 ◽  
Vol 83 (3) ◽  
pp. 1247-1281 ◽  
Author(s):  
DÁNIEL T. SOUKUP ◽  
LAJOS SOUKUP
Keyword(s):  
Chromatic Number ◽  
Set Theory ◽  
Wide Applicability ◽  
Elementary Submodels ◽  
Set Systems ◽  
Point Set ◽  
Infinite Combinatorics ◽  
Sparse Set ◽  
Paradoxical Decompositions ◽  
General Method

AbstractWe explore a general method based on trees of elementary submodels in order to present highly simplified proofs to numerous results in infinite combinatorics. While countable elementary submodels have been employed in such settings already, we significantly broaden this framework by developing the corresponding technique for countably closed models of size continuum. The applications range from various theorems on paradoxical decompositions of the plane, to coloring sparse set systems, results on graph chromatic number and constructions from point-set topology. Our main purpose is to demonstrate the ease and wide applicability of this method in a form accessible to anyone with a basic background in set theory and logic.

Matter and Point Set Theory

1960 ◽  
Vol 117 (5) ◽  
pp. 1409-1409
Author(s):  
Ali Kyrala
Keyword(s):  
Set Theory ◽  
Point Set

Foundations of Point Set Theory

1934 ◽  
Vol 18 (231) ◽  
pp. 325
Author(s):  
P. J. D. ◽  
R. L. Moore
Keyword(s):  
Set Theory ◽  
Point Set

Analysis, philosophical issues in

2018 ◽  
Author(s):  
I. Grattan-Guinness
Keyword(s):  
Eighteenth Century ◽  
Seventeenth Century ◽  
Set Theory ◽  
Integral Calculus ◽  
Analytic Proof ◽  
Isaac Newton ◽  
The Status ◽  
Point Set ◽  
Convergence And Divergence ◽  
Major Branch

The term ‘mathematical analysis’ refers to the major branch of mathematics which is concerned with the theory of functions and includes the differential and integral calculus. Analysis and the calculus began as the study of curves, calculus being concerned with tangents to and areas under curves. The focus was shifted to functions following the insight, due to Leibniz and Isaac Newton in the second half of the seventeenth century, that a curve is the graph of a function. Algebraic foundations were proposed by Lagrange in the late eighteenth century; assuming that any function always took an expansion in a power series, he defined the derivatives from the coefficients of the terms. In the 1820s his assumption was refuted by Cauchy, who had already launched a fourth approach, like Newton’s based on limits, but formulated much more carefully. It was refined further by Weierstrass, by means which helped to create set theory. Analysis also encompasses the theory of limits and of the convergence and divergence of infinite series; modern versions also use point set topology. It has taken various forms over the centuries, of which the older ones are still represented in some notations and terms. Philosophical issues include the status of infinitesimals, the place of logic in the articulation of proofs, types of definition, and the (non-) relationship to analytic proof methods.

A minimal counterexample to universal baireness

1999 ◽  
Vol 64 (4) ◽  
pp. 1601-1627 ◽  
Author(s):  
Kai Hauser
Keyword(s):  
Fine Structure ◽  
Set Theory ◽  
Canonical Model ◽  
Core Model ◽  
Real Numbers ◽  
The Real ◽  
Minimal Counterexample ◽  
General Method ◽  
The Way

AbstractFor a canonical model of set theory whose projective theory of the real numbers is stable under set forcing extensions, a set of reals of minimal complexity is constructed which fails to be universally Baire. The construction uses a general method for generating non-universally Baire sets via the Levy collapse of a cardinal, as well as core model techniques. Along the way it is shown (extending previous results of Steel) how sufficiently iterable fine structure models recognize themselves as global core models.

scholarly journals A Soft Interval Based Decision Making Method and Its Computer Application

2021 ◽  
Vol 46 (3) ◽  
pp. 273-296
Author(s):  
Gözde Yaylalı ◽  
Nazan Çakmak Polat ◽  
Bekir Tanay
Keyword(s):  
Decision Making ◽  
Set Theory ◽  
Soft Set ◽  
Computer Application ◽  
Complex Data ◽  
Soft Sets ◽  
Mathematical Algorithm ◽  
Huge Data ◽  
Special Cases ◽  
General Method

Abstract In today’s society, decision making is becoming more important and complicated with increasing and complex data. Decision making by using soft set theory, herein, we firstly report the comparison of soft intervals (SI) as the generalization of interval soft sets (ISS). The results showed that SIs are more effective and more general than the ISSs, for solving decision making problems due to allowing the ranking of parameters. Tabular form of SIs were used to construct a mathematical algorithm to make a decision for problems that involves uncertainties. Since these kinds of problems have huge data, constructing new and effective methods solving these problems and transforming them into the machine learning methods is very important. An important advance of our presented method is being a more general method than the Decision-Making methods based on special situations of soft set theory. The presented method in this study can be used for all of them, while the others can only work in special cases. The structures obtained from the results of soft intervals were subjected to test with examples. The designed algorithm was written in recently used functional programing language C# and applied to the problems that have been published in earlier studies. This is a pioneering study, where this type of mathematical algorithm was converted into a code and applied successfully.

Questions of generality as probes into nineteenth-century mathematical analysis

2017 ◽  
Author(s):  
Renaud Chorlay
Keyword(s):  
Nineteenth Century ◽  
Set Theory ◽  
Mathematical Analysis ◽  
Analytic Functions ◽  
Function Theory ◽  
The Third ◽  
Point Set

This article examines ways of expressing generality and epistemic configurations in which generality issues became intertwined with epistemological topics, such as rigor, or mathematical topics, such as point-set theory. In this regard, three very specific configurations are discussed: the first evolving from Niels Henrik Abel to Karl Weierstrass, the second in Joseph-Louis Lagrange’s treatises on analytic functions, and the third in Emile Borel. Using questions of generality, the article first compares two major treatises on function theory, one by Lagrange and one by Augustin Louis Cauchy. It then explores how some mathematicians adopted the sophisticated point-set theoretic tools provided for by the advocates of rigor to show that, in some way, Lagrange and Cauchy had been right all along. It also introduces the concept of embedded generality for capturing an approach to generality issues that is specific to mathematics.

scholarly journals CONTINUITY OF UNIVERSALLY MEASURABLE HOMOMORPHISMS

2019 ◽  
Vol 7 ◽  
Author(s):  
CHRISTIAN ROSENDAL
Keyword(s):  
New York ◽  
Functional Analysis ◽  
Chromatic Number ◽  
Set Theory ◽  
Measure Theory ◽  
Polish Groups ◽  
Hamming Graph ◽  
Borel Structure ◽  
North Holland Publishing ◽  
Haar Null Sets

Answering a longstanding problem originating in Christensen’s seminal work on Haar null sets [Math. Scand. 28 (1971), 124–128; Israel J. Math. 13 (1972), 255–260; Topology and Borel Structure. Descriptive Topology and Set Theory with Applications to Functional Analysis and Measure Theory, North-Holland Mathematics Studies, 10 (Notas de Matematica, No. 51). (North-Holland Publishing Co., Amsterdam–London; American Elsevier Publishing Co., Inc., New York, 1974), iii+133 pp], we show that a universally measurable homomorphism between Polish groups is automatically continuous. Using our general analysis of continuity of group homomorphisms, this result is used to calibrate the strength of the existence of a discontinuous homomorphism between Polish groups. In particular, it is shown that, modulo $\text{ZF}+\text{DC}$ , the existence of a discontinuous homomorphism between Polish groups implies that the Hamming graph on $\{0,1\}^{\mathbb{N}}$ has finite chromatic number.

NOTE ON POINT SET THEORY

1989 ◽  
Vol 15 (1) ◽  
pp. 410
Author(s):  
Morgan
Keyword(s):  
Set Theory ◽  
Point Set
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