Generalized Effect Algebras Research Articles

Associativity and Distributivity-Like Properties in Generalized Effect Algebras

Associativity and Distributivity-Like Properties in Generalized Effect Algebras

Some properties of D-weak operator topology

Abstract Let 𝓖 D (𝓗) denote the generalized effect algebra consisting of all positive linear operators defined on a dense linear subspace D of a Hilbert space 𝓗. The D-weak operator topology (introduced by other authors) on 𝓖 D (𝓗) is investigated. The corresponding closure of the set of bounded elements of 𝓖 D (𝓗) is the whole 𝓖 D (𝓗). The closure of the set of all unbounded elements of 𝓖 D (𝓗) is also the set 𝓖 D (𝓗). If Q is arbitrary unbounded element of 𝓖 D (𝓗), it determines an interval in 𝓖 D (𝓗), consisting of all operators between 0 and Q (with the usual ordering of operators). If we take the set of all bounded elements of this interval, the closure of this set (in the D-weak operator topology) is just the original interval. Similarly, the corresponding closure of the set of all unbounded elements of the interval will again be the considered interval.

Generalized pseudo-EMV-effect algebras

EMV-algebras were recently introduced in Dvurecenskij and Zahiri (Fuzzy Sets Syst, 2019. https://doi.org/10.1016/j.fss.2019.02.013 ) as new structures generalizing both MV-algebras and Boolean rings. These algebras do not assume that they contain a top element. We present a non-commutative generalization of EMV-algebras, called pseudo-EMV-algebras. We show how from a pseudo-EMV-algebra we can derive a generalized pseudo-EMV-effect algebra and conversely, from a generalized effect algebra with a stronger type of the Riesz decomposition property we can derive a pseudo-EMV-algebra. We show that every generalized pseudo-EMV-effect algebra without top element can be embedded into a pseudo-MV-effect algebra with top element as a maximal and normal ideal of the pseudo-MV-effect algebra.

EMV-pairs

ABSTRACTThe class of EMV-algebras and the class of lattice generalized effect algebras with RDP which have enough idempotents (EMV-effect algebra for short) are termwise equivalent. We use it to generalize connections between MV-algebras and MV-pairs for the case of EMV-algebras. First, we show that each EMV-algebra M is a homomorphic image of , the generalized Boolean algebra R-generated by M. Then we introduce a concept of an EMV-pair and construct an EMV-algebra using the EMV-pair. We also show that each EMV-algebra can be induced in this way. Then, the concept of an EMV-pair as a generalization of an MV-pair is introduced and some related results are obtained. Finally, we study G-invariant ideals of an EMV-pair .

On Monoids in the Category of Sets and Relations

The category $\mathbf{Rel}$ is the category of sets (objects) and relations (morphisms). Equipped with the direct product of sets, $\mathbf{Rel}$ is a monoidal category. Moreover, $\mathbf{Rel}$ is a locally posetal 2-category, since every homset $\mathbf{Rel}(A,B)$ is a poset with respect to inclusion. We examine the 2-category of monoids $\mathbf{RelMon}$ in this category. The morphism we use are lax. This category includes, as subcategories, various interesting classes: hypergroups, partial monoids (which include various types of quantum logics, for example effect algebras) and small categories. We show how the 2-categorical structure gives rise to several previously defined notions in these categories, for example certain types of congruence relations on generalized effect algebras. This explains where these definitions come from.

On realization of effect algebras

Abstract A well known fact is that there is a finite orthomodular lattice with an order determining set of states which is not order embeddable into the standard quantum logic, the lattice L(𝓗) of all closed subspaces of a separable complex Hilbert space. We show that a finite generalized effect algebra is order embeddable into the standard effect algebra E(𝓗) of effects of a separable complex Hilbert space iff it has an order determining set of generalized states iff it is order embeddable into the power of a finite MV-chain. As an application we obtain an algorithm, which is based on the simplex algorithm, deciding whether such an order embedding exists and, if the answer is positive, constructing it.

A note on unitizations of generalized effect algebras

There is a forgetful functor from the category of generalized effect algebras to the category of effect algebras. We prove that this functor is a right adjoint and that the corresponding left adjoint is the well-known unitization construction by Hedl\'ikov\'a and Pulmannov\'a. Moreover, this adjunction is monadic.

Regular Gleason Measures and Generalized Effect Algebras

We study measures, finitely additive measures, regular measures, and σ-additive measures that can attain even infinite values on the quantum logic of a Hilbert space. We show when particular classes of non-negative measures can be studied in the frame of generalized effect algebras.

Top Element Problem and Macneille Completions of Generalized Effect Algebras

Effect algebras (EAs), introduced by D. J. Foulis and M. K. Bennett, as common generalizations of Boolean algebras, orthomodular lattices and MV-algebras, are nondistributive algebraic structures including unsharp elements. Their unbounded versions, called generalized effect algebras, are posets which may have or may have not an EA-MacNeille completion, or cannot be embedded into any complete effect algebra. We give a necessary and sufficient condition for a generalized effect algebra to have an EA-MacNeille completion. Some examples are provided.

Unitizing a Generalized Pseudo Effect Algebra

As is well-known, every generalized effect algebra can be embedded as a maximal proper ideal in an effect algebra called its unitization. We show that a necessary and sufficient condition that a generalized pseudo effect algebra can similarly be embedded as a maximal proper ideal in a pseudo effect algebra is that it admits a so-called unitizing automorphism. On the other hand, we show that a pseudo effect algebra is a unitization of a generalized pseudo effect algebra if and only if it admits a two-valued state.

Generalized Effect Algebras of Positive Self-adjoint Linear Operators on Hilbert Spaces

In this paper, we introduce a partially defined binary operation on the set \(S^{+}(\mathcal {H})\) of all positive self-adjoint linear operators on a complex Hilbert space \(\mathcal {H}\), which makes the set into a generalized effect algebra. Moreover, we present two kinds of partial orders on \(S^{+}(\mathcal {H})\) and give the relationship of the two orders. We study two important topologies on \(S^{+}(\mathcal {H})\), too.

Representation of Concrete Logics and Concrete Generalized Orthomodular Posets

In the present paper, we deal with the question when an effect algebra, resp. a generalized effect algebra, can be represented in the projection lattice of a Hilbert space. We show that such representability is closely related to the existence of a rich set of two-valued and Jauch–Piron states, resp. generalized two-valued and Jauch–Piron states. AMS Classification : Primary 81Q10, Secondary 03G12.

Blocks in Pairwise Summable Generalized Effect Algebras

We study the so-called pairwise summable generalized effect algebras and show some conditions under which they are generalized MV-effect algebras. Moreover, we give a necessary and sufficient condition for finite antichains of elements in pairwise summable generalized effect algebras under which they are sets of atoms of sub-generalized effect algebras, which are generalized MV-effect algebras in their own right. Simultaneously, we give counterexamples which show properties of those antichains which are not necessary or sufficient to be atoms of such generalized MV-effect algebras.

The Center Of A Generalized Effect Algebra

AbstractIn this article, we study the center of a generalized effect algebra (GEA), relate it to the exocenter, and in case the GEA is centrally orthocomplete (a COGEA), relate it to the exocentral cover system. Our main results are that the center of a COGEA is a complete boolean algebra and that a COGEA decomposes uniquely as the direct sum of an effect algebra (EA) that contains the center of the COGEA and a complementary direct summand in which no nonzero direct summand is an EA.

MAXIMAL SUBSETS OF PAIRWISE SUMMABLE ELEMENTS IN GENERALIZED EFFECT ALGEBRAS

We show that in any generalized effect algebra (G;⊕, 0) a maximal pairwise summable subset is a sub-generalized effect algebra of (G;⊕, 0), called a summability block. If G is lattice ordered, then every summability block in G is a generalized MV-effect algebra. Moreover, if every element of G has an infinite isotropic index, then G is covered by its summability blocks, which are generalized MV-effect algebras in the case that G is lattice ordered. We also present the relations between summability blocks and compatibility blocks of G. Counterexamples, to obtain the required contradictions in some cases, are given.

On Bilinear Forms from the Point of View of Generalized Effect Algebras

We study positive bilinear forms on a Hilbert space which are not necessarily bounded nor induced by some positive operator. We show when different families of bilinear forms can be described as a generalized effect algebra. In addition, we present families which are or are not monotone downwards (Dedekind upwards) σ-complete generalized effect algebras.

Intervals in generalized effect algebras

A significant property of a generalized effect algebra is that its every interval with inherited partial sum is an effect algebra. We show that in some sense the converse is also true. More precisely, we prove that a set with zero element is a generalized effect algebra if and only if all its intervals are effect algebras. We investigate inheritance of some properties from intervals to generalized effect algebras, e.g., the Riesz decomposition property, compatibility of every pair of elements, dense embedding into a complete effect algebra, to be a sub-(generalized) effect algebra, to be lattice ordered and others. The response to the Open Problem from Rieă?anova and Zajac (2013) for generalized effect algebras and their sub-generalized effect algebras is given.

Dimension theory for generalized effect algebras

In this paper, we define and study dimension generalized effect algebras (DGEAs), i.e., Dedekind orthocomplete and centrally orthocomplete generalized effect algebras equipped with a dimension equivalence relation. Our theory is a bona fide generalization of the theory of dimension effect algebras (DEAs), i.e., it is formulated so that if a DGEA happens to be an effect algebra (i.e., it has a unit element), then it is a DEA. We prove that a DGEA decomposes into type I, II, and III DGEAS in a manner analogous to the type I/II/III decomposition of a DEA.

Intervals in Generalized Effect Algebras and their Sub-generalized Effect Algebras

We consider subsets G of a generalized effect algebra E with 0∈G and such that every interval [0, q]G = [0, q]E ∩ G of G (q ∈ G , q ≠ 0) is a sub-effect algebra of the effect algebra [0, q]E. We give a condition on E and G under which every such G is a sub-generalized effect algebra of E.

Weakly Ordered A-Commutative Partial Groups of Linear Operators Densely Defined on Hilbert Space

The notion of a generalized effect algebra is presented as a generalization of effect algebra for an algebraic description of the structure of the set of all positive linear operators densely defined on a Hilbert space with the usual sum of operators. The structure of the set of not only positive linear operators can be described with the notion of a weakly ordered partial commutative group (wop-group).Due to the non-constructive algebraic nature of the wop-group we introduce its stronger version called a weakly ordered partial a-commutative group (woa-group). We show that it also describes the structure of not only positive linear operators.