Preface to the special volume: “Chu spaces: theory and applications".
Prefix classes of Krom formulae with identity.
Preliminaries to Classical First Order Model Theory
First of a series of articles laying down the bases for classical first order model theory. These articles introduce a framework for treating arbitrary languages with equality. This framework is kept as generic and modular as possible: both the language and the derivation rule are introduced as a type, rather than a fixed functor; definitions and results regarding syntax, semantics, interpretations and sequent derivation rules, respectively, are confined to separate articles, to mark out the hierarchy...
Prenormality of ideals and completeness of their quotient algebras
It is well known that if a nontrivial ideal ℑ on κ is normal, its quotient Boolean algebra P(κ)/ℑ is -complete. It is also known that such completeness of the quotient does not characterize normality, since P(κ)/ℑ turns out to be -complete whenever ℑ is prenormal, i.e. whenever there exists a minimal ℑ-measurable function in . Recently, it has been established by Zrotowski (see [Z1], [CWZ] and [Z2]) that for non-Mahlo κ, not only is the above condition sufficient but also necessary for P(κ)/ℑ...
Prescribing endomorphism algebras of -free modules
It is a well-known fact that modules over a commutative ring in general cannot be classified, and it is also well-known that we have to impose severe restrictions on either the ring or on the class of modules to solve this problem. One of the restrictions on the modules comes from freeness assumptions which have been intensively studied in recent decades. Two interesting, distinct but typical examples are the papers by Blass [1] and Eklof [8], both jointly with Shelah. In the first case the authors...
Prescribing endomorphism algebras. The cotorsion-free case
Présentation de la logique combinatoire en vue de ses applications
Presentation of Natural Deduction
Preservation of admissibility of inference rules in the logics similar to S4. 2.
Preservation of properties of fuzzy relations during aggregation processes
Diverse classes of fuzzy relations such as reflexive, irreflexive, symmetric, asymmetric, antisymmetric, connected, and transitive fuzzy relations are studied. Moreover, intersections of basic relation classes such as tolerances, tournaments, equivalences, and orders are regarded and the problem of preservation of these properties by -ary operations is considered. Namely, with the use of fuzzy relations and -argument operation on the interval , a new fuzzy relation is created. Characterization...
Preservation of the Borel class under open-LC functions
Let X be a Borel subset of the Cantor set C of additive or multiplicative class α, and f: X → Y be a continuous function onto Y ⊂ C with compact preimages of points. If the image f(U) of every clopen set U is the intersection of an open and a closed set, then Y is a Borel set of the same class α. This result generalizes similar results for open and closed functions.
Preservation Theorems for Limits of Structures and Global Sections of Sheaves of Structures.
Preserving P-points in definable forcing
I isolate a simple condition that is equivalent to preservation of P-points in definable proper forcing.
Preserving some properties of large cardinals under mild Cohen extensions
Priestley dualities for some lattice-ordered algebraic structures, including MTL, IMTL and MV-algebras
In this work we give a duality for many classes of lattice ordered algebras, as Integral Commutative Distributive Residuated Lattices MTL-algebras, IMTL-algebras and MV-algebras (see page 604). These dualities are obtained by restricting the duality given by the second author for DLFI-algebras by means of Priestley spaces with ternary relations (see [2]). We translate the equations that define some known subvarieties of DLFI-algebras to relational conditions in the associated DLFI-space.
Primariness of some spaces of continuous functions.
Prime and maximal ideals of partially ordered sets
Prime Factorization of Sums and Differences of Two Like Powers
Representation of a non zero integer as a signed product of primes is unique similarly to its representations in various types of positional notations [4], [3]. The study focuses on counting the prime factors of integers in the form of sums or differences of two equal powers (thus being represented by 1 and a series of zeroes in respective digital bases). Although the introduced theorems are not particularly important, they provide a couple of shortcuts useful for integer factorization, which could...
Prime Filters and Ideals in Distributive Lattices
The article continues the formalization of the lattice theory (as structures with two binary operations, not in terms of ordering relations). In the Mizar Mathematical Library, there are some attempts to formalize prime ideals and filters; one series of articles written as decoding [9] proven some results; we tried however to follow [21], [12], and [13]. All three were devoted to the Stone representation theorem [18] for Boolean or Heyting lattices. The main aim of the present article was to bridge...
Prime ideal theorem for double Boolean algebras
Double Boolean algebras are algebras (D,⊓,⊔,⊲,⊳,⊥,⊤) of type (2,2,1,1,0,0). They have been introduced to capture the equational theory of the algebra of protoconcepts. A filter (resp. an ideal) of a double Boolean algebra D is an upper set F (resp. down set I) closed under ⊓ (resp. ⊔). A filter F is called primary if F ≠ ∅ and for all x ∈ D we have x ∈ F or . In this note we prove that if F is a filter and I an ideal such that F ∩ I = ∅ then there is a primary filter G containing F such that G...