On sets not belonging to algebras

2007 ◽  
Vol 72 (2) ◽  
pp. 483-500 ◽  
Author(s):  
L. Š. Grinblat
Keyword(s):  
Pairwise Disjoint ◽  
Finite Sequence ◽  
Countable Sequence ◽  
Finite Sequences ◽  
Disjoint Sets ◽  
Algebras Of Sets

AbstractLet be a finite sequence of algebras of sets given on a set with more than pairwise disjoint sets not belonging to It was shown in [4] and [5] that in this case Let us consider, instead a finite sequence of algebras It turns out that if for each natural i ≤ l there exist no less than pairwise disjoint sets not belonging to then But if l ≥ 195 and if for each natural i ≤ l there exist no less than pairwise disjoint sets not belonging to then After consideration of finite sequences of algebras, it is natural to consider countable sequences of algebras. We obtained two essentially important theorems on a countable sequence of almost σ-algebras (the concept of almost σ-algebra was introduced in [4]).

scholarly journals Concatenation of Finite Sequences

2019 ◽  
Vol 27 (1) ◽  
pp. 1-13
Author(s):  
Rafał Ziobro
Keyword(s):  
Finite Sequence ◽  
The Other ◽  
Other Hand ◽  
Finite Sequences ◽  
Initial Object

Summary The coexistence of “classical” finite sequences [1] and their zero-based equivalents finite 0-sequences [6] in Mizar has been regarded as a disadvantage. However the suggested replacement of the former type with the latter [5] has not yet been implemented, despite of several advantages of this form, such as the identity of length and domain operators [4]. On the other hand the number of theorems formalized using finite sequence notation is much larger then of those based on finite 0-sequences, so such translation would require quite an effort. The paper addresses this problem with another solution, using the Mizar system [3], [2]. Instead of removing one notation it is possible to introduce operators which would concatenate sequences of various types, and in this way allow utilization of the whole range of formalized theorems. While the operation could replace existing FS2XFS, XFS2FS commands (by using empty sequences as initial elements) its universal notation (independent on sequences that are concatenated to the initial object) allows to “forget” about the type of sequences that are concatenated on further positions, and thus simplify the proofs.

scholarly journals Families with no s pairwise disjoint sets

2017 ◽  
Vol 95 (3) ◽  
pp. 875-894 ◽  
Author(s):  
Peter Frankl ◽  
Andrey Kupavskii
Keyword(s):  
Pairwise Disjoint ◽  
Disjoint Sets

Strongs-Sequences and Variations on Martin's Axiom

1985 ◽  
Vol 37 (4) ◽  
pp. 730-746 ◽  
Author(s):  
Juris Steprāns
Keyword(s):  
Pairwise Disjoint ◽  
Disjoint Family ◽  
Uncountable Family ◽  
Martin’S Axiom ◽  
Finite Set ◽  
Almost Disjoint ◽  
Disjoint Sets ◽  
Almost Disjoint Family ◽  
Require Equality ◽  
Single Set

As part of their study of βω — ω and βω1 — ω1, A. Szymanski and H. X. Zhou [3] were able to exploit the following difference between ω, and ω: ω1, contains uncountably many disjoint sets whereas any uncountable family of subsets of ω is, at best, almost disjoint. To translate this distinction between ω1, and ω to a possible distinction between βω1 — ω1, and βω — ω they used the fact that if a pairwise disjoint family of sets and a subset of each member of is chosen then it is trivial to find a single set whose intersection with each member is the chosen set. However, they noticed, it is not clear that the same is true if is only a pairwise almost disjoint family even if we only require equality except on a finite set. But any homeomorphism from βω1 — ω1 to βω — ω would have to carry a disjoint family of subsets of ω1, to an almost disjoint family of subsets of ω with this property. This observation should motivate the following definition.

scholarly journals Fitting classes and lattice formations I

2004 ◽  
Vol 76 (1) ◽  
pp. 93-108 ◽  
Author(s):  
M. Arroyo-Jordá ◽  
M. D. Pérez-Ramos
Keyword(s):  
Direct Product ◽  
Pairwise Disjoint ◽  
Nilpotent Groups ◽  
Saturated Formation ◽  
Closure Properties ◽  
Soluble Groups ◽  
Hall Subgroups ◽  
Disjoint Sets ◽  
Lattice Formation ◽  
Fitting Classes

AbstractA lattice formation is a class of groups whose elements are the direct product of Hall subgroups corresponding to pairwise disjoint sets of primes. In this paper Fitting classes with stronger closure properties involving F-subnormal subgroups, for a lattice formation F of full characteristic, are studied. For a subgroup-closed saturated formation G, a characterisation of the G-projectors of finite soluble groups is also obtained. It is inspired by the characterisation of the Carter subgroups as the N-projectors, N being the class of nilpotent groups.

The foundations of Suslin logic

1975 ◽  
Vol 40 (4) ◽  
pp. 567-575 ◽  
Author(s):  
Erik Ellentuck
Keyword(s):  
Finite Sequence ◽  
Order Logic ◽  
First Order Logic ◽  
Infinitary Logic ◽  
First Order ◽  
Finite Sequences ◽  
Image Position

Let L be a first order logic and the infinitary logic (as described in [K, p. 6] over L. Suslin logic is obtained from by adjoining new propositional operators and . Let f range over elements of ωω and n range over elements of ω. Seq is the set of all finite sequences of elements of ω. If θ: Seq → is a mapping into formulas of then and are formulas of LA. If is a structure in which we can interpret and h is an -assignment then we extend the notion of satisfaction from to by definingwhere f ∣ n is the finite sequence consisting of the first n values of f. We assume that has ω symbols for relations, functions, constants, and ω1 variables. θ is valid if θ ⊧ [h] for every h and is valid if -valid for every . We address ourselves to the problem of finding syntactical rules (or nearly so) which characterize validity .

scholarly journals Introduction to Liouville Numbers

2017 ◽  
Vol 25 (1) ◽  
pp. 39-48
Author(s):  
Adam Grabowski ◽  
Artur Korniłowicz
Keyword(s):  
Positive Integer ◽  
Algebraic Number ◽  
Finite Sequence ◽  
Rational Numbers ◽  
Liouville Number ◽  
Liouville Numbers ◽  
Constant Sequence ◽  
Transcendental Numbers ◽  
Finite Sequences ◽  
Definition Of

Summary The article defines Liouville numbers, originally introduced by Joseph Liouville in 1844 [17] as an example of an object which can be approximated “quite closely” by a sequence of rational numbers. A real number x is a Liouville number iff for every positive integer n, there exist integers p and q such that q > 1 and It is easy to show that all Liouville numbers are irrational. Liouville constant, which is also defined formally, is the first transcendental (not algebraic) number. It is defined in Section 6 quite generally as the sum for a finite sequence {ak}k∈ℕ and b ∈ ℕ. Based on this definition, we also introduced the so-called Liouville number as substituting in the definition of L(ak, b) the constant sequence of 1’s and b = 10. Another important examples of transcendental numbers are e and π [7], [13], [6]. At the end, we show that the construction of an arbitrary Lioville constant satisfies the properties of a Liouville number [12], [1]. We show additionally, that the set of all Liouville numbers is infinite, opening the next item from Abad and Abad’s list of “Top 100 Theorems”. We show also some preliminary constructions linking real sequences and finite sequences, where summing formulas are involved. In the Mizar [14] proof, we follow closely https://en.wikipedia.org/wiki/Liouville_number. The aim is to show that all Liouville numbers are transcendental.

Two Isomorphic 9 Order Steiner Triple Systems Large Sets

2013 ◽  
Vol 427-429 ◽  
pp. 1237-1240
Author(s):  
Zhao Di Xu ◽  
Xiao Yi Li ◽  
Wan Xi Chou
Keyword(s):  
Pairwise Disjoint ◽  
Permutation Matrix ◽  
Large Set ◽  
Steiner Triple Systems ◽  
Triple Systems ◽  
Large Sets ◽  
Initial Block ◽  
Disjoint Sets ◽  
Basic Ideas ◽  
Block Permutation

This paper Clarifies the basic ideas of constructing the v order Steiner triple systems. This paper proposed the construction method of pairwise disjoint sets s(i)(v) for Steiner triple systems based on the initial block permutation matrix. And a method of initial block permutation matrix is given. This paper also introduced the entire construction process of two isomorphic 9 order Steiner triple systems large set. At last, this paper proved the number of pairwise disjoint forsi(9)is d(9)=7 .

On an algebra of sets of finite sequences

1970 ◽  
Vol 35 (1) ◽  
pp. 19-28 ◽  
Author(s):  
J. Donald Monk
Keyword(s):  
Infinite Sequence ◽  
Finite Sequence ◽  
Order Logic ◽  
First Order Logic ◽  
Cylindric Algebras ◽  
First Order ◽  
Basic Model ◽  
Finite Sequences ◽  
Individual Variables ◽  
Algebra Of Sets

The algebras studied in this paper were suggested to the author by William Craig as a possible substitute for cylindric algebras. Both kinds of algebras may be considered as algebraic versions of first-order logic. Cylindric algebras can be introduced as follows. Let ℒ be a first-order language, and let be an ℒ-structure. We assume that ℒ has a simple infinite sequence ν0, ν1, … of individual variables, and we take as known what it means for a sequence ν0, ν1, … of individual variables, and we take as known what it means for a sequence x = 〈x0, x1, …〉 of elements of to satisfy a formula ϕ of ℒ in . Let ϕ be the collection of all sequences x which satisfy ϕ in . We can perform certain natural operations on the sets ϕ, of basic model-theoretic significance: Boolean operations = cylindrifications diagonal elements (0-ary operations) . In this way we make the class of all sets ϕ into an algebra; a natural abstraction gives the class of all cylindric set algebras (of dimension ω). Thus this method of constructing an algebraic counterpart of first-order logic is based upon the notion of satisfaction of a formula by an infinite sequence of elements. Since, however, a formula has only finitely many variables occurring in it, it may seem more natural to consider satisfaction by a finite sequence of elements; then ϕ becomes a collection of finite sequences of varying ranks (cf. Tarski [10]). In forming an algebra of sets of finite sequences it turns out to be possible to get by with only finitely many operations instead of the infinitely many ci's and dij's of cylindric algebras. Let be the class of all algebras of sets of finite sequences (an exact definition is given in §1).

scholarly journals Definition and some Properties of Information Entropy

2007 ◽  
Vol 15 (3) ◽  
pp. 111-119
Author(s):  
Bo Zhang ◽  
Yatsuka Nakamura
Keyword(s):  
Information Entropy ◽  
Finite Sequence ◽  
Basic Properties ◽  
Maximum Property ◽  
Finite Sequences ◽  
Transformation Functions ◽  
Probability Matrices ◽  
Concept Of Information ◽  
Properties Of Information ◽  
The Given

Definition and some Properties of Information EntropyIn this article we mainly define the information entropy [3], [11] and prove some its basic properties. First, we discuss some properties on four kinds of transformation functions between vector and matrix. The transformation functions are LineVec2Mx, ColVec2Mx, Vec2DiagMx and Mx2FinS. Mx2FinS is a horizontal concatenation operator for a given matrix, treating rows of the given matrix as finite sequences, yielding a new finite sequence by horizontally joining each row of the given matrix in order to index. Then we define each concept of information entropy for a probability sequence and two kinds of probability matrices, joint and conditional, that are defined in article [25]. Further, we discuss some properties of information entropy including Shannon's lemma, maximum property, additivity and super-additivity properties.

scholarly journals About Quotient Orders and Ordering Sequences

2017 ◽  
Vol 25 (2) ◽  
pp. 121-139
Author(s):  
Sebastian Koch
Keyword(s):  
Finite Subset ◽  
Finite Sequence ◽  
Relational Structure ◽  
Real Numbers ◽  
Natural Restriction ◽  
Relational Structures ◽  
The Third ◽  
Finite Sequences ◽  
Directed Walks ◽  
Ordered Pairs

Summary In preparation for the formalization in Mizar [4] of lotteries as given in [14], this article closes some gaps in the Mizar Mathematical Library (MML) regarding relational structures. The quotient order is introduced by the equivalence relation identifying two elements x, y of a preorder as equivalent if x ⩽ y and y ⩽ x. This concept is known (see e.g. chapter 5 of [19]) and was first introduced into the MML in [13] and that work is incorporated here. Furthermore given a set A, partition D of A and a finite-support function f : A → ℝ, a function Σf : D → ℝ, Σf (X)= ∑x∈X f(x) can be defined as some kind of natural “restriction” from f to D. The first main result of this article can then be formulated as: $$\sum\limits_{x \in A} {f(x)} = \sum\limits_{X \in D} {\Sigma _f (X)\left( { = \sum\limits_{X \in D} {\sum\limits_{x \in X} {f(x)} } } \right)} $$ After that (weakly) ascending/descending finite sequences (based on [3]) are introduced, in analogous notation to their infinite counterparts introduced in [18] and [13]. The second main result is that any finite subset of any transitive connected relational structure can be sorted as a ascending or descending finite sequence, thus generalizing the results from [16], where finite sequence of real numbers were sorted. The third main result of the article is that any weakly ascending/weakly descending finite sequence on elements of a preorder induces a weakly ascending/weakly descending finite sequence on the projection of these elements into the quotient order. Furthermore, weakly ascending finite sequences can be interpreted as directed walks in a directed graph, when the set of edges is described by ordered pairs of vertices, which is quite common (see e.g. [10]). Additionally, some auxiliary theorems are provided, e.g. two schemes to find the smallest or the largest element in a finite subset of a connected transitive relational structure with a given property and a lemma I found rather useful: Given two finite one-to-one sequences s, t on a set X, such that rng t ⊆ rng s, and a function f : X → ℝ such that f is zero for every x ∈ rng s \ rng t, we have ∑ f o s = ∑ f o t.

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