Associative,Idempotent, Symmetric,and Order-preserving Operations on Chains

We characterize the associative, idempotent, symmetric, and order-preserving binary operations on (finite) chains in terms of properties of (the Hasse diagram of) their associated semilattice order. In particular, we prove that the number of associative, idempotent, symmetric, and order-preserving operations on an n-element chain is the n^th Catalan number.

     

Structure of free strong doppelsemigroups

We consider strong doppelsemigroups which are sets with two binary associative operations satisfying axioms of strong interassociativity. Commutative dimonoids in the sense of Loday are examples of strong doppelsemigroups and two strongly interassociative semigroups give rise to a strong doppelsemigroup. The main aim of this paper is to construct a free strong doppelsemigroup, a free n-dinilpotent strong doppelsemigroup, a free commutative strong doppelsemigroup and a free n-nilpotent strong doppelsemigroup. We also characterize the least n-dinilpotent congruence, the least commutative congruence, the least n-nilpotent congruence on a free strong doppelsemigroup and establish that the automorphism group of every constructed free algebra is isomorphic to the symmetric group.     

Multiplication product formula for associated homogeneous distributions on R

The set of associated homogeneous distributions (AHDs) on R, ??^′(R), consists of the distributional analogues of power‐log functions with domain in R. This set contains the majority of the (one‐dimensional) distributions one typically encounters in physics applications. The recent work done by the author showed that the set ??^′(R) admits a closed convolution structure (??^′(R), *). By combining this structure with the generalized convolution theorem, a distributional multiplication product was defined, resulting in also a closed multiplication structure (??^′(R), .). In this paper, the general multiplication product formula for this structure is derived. Multiplication of AHDs on R is associative, except for critical triple products. These critical products are shown to be non‐associative in a simple and interesting way. The non‐associativity is necessary and sufficient to circumvent Schwartz's impossibility theorem on the multiplication of distributions. Copyright © 2011 John Wiley & Sons, Ltd.     

Polynomial Identities for Tangent Algebras of Monoassociative Loops

We introduce degree n Sabinin algebras, which are defined by the polynomial identities up to degree n in a Sabinin algebra. Degree 4 Sabinin algebras can be characterized by the polynomial identities satisfied by the commutator, associator, and two quaternators in the free nonassociative algebra. We consider these operations in a free power associative algebra and show that one of the quaternators is redundant. The resulting algebras provide the natural structure on the tangent space at the identity element of an analytic loop for which all local loops satisfy monoassociativity, a ² a ≡ aa ². These algebras are the next step beyond Lie, Malcev, and Bol algebras. We also present an identity of degree 5 which is satisfied by these three operations but which is not implied by the identities of lower degree.     

Free left n-dinilpotent doppelsemigroups

A doppelsemigroup is an algebraic system consisting of a set with two binary associative operations satisfying certain equations. Commutative dimonoids in the sense of Loday are examples of doppelsemigroups and two interassociative semigroups give rise to a doppelsemigroup. We introduce left (right) n-dinilpotent doppelsemigroups which are analogs of left (right) nilpotent semigroups of rank n considered by Schein. A free left (right) n-dinilpotent doppelsemigroup is constructed and the least left (right) n-dinilpotent congruence on a free doppelsemigroup is characterized. We also establish that the semigroups of the free left (right) n-dinilpotent doppelsemigroup are isomorphic and the automorphism group of the free left (right) n-dinilpotent doppelsemigroup is isomorphic to the symmetric group.     

Convolution product formula for associated homogeneous distributions on R

The set of Associated Homogeneous Distributions (AHDs) on R, ??′(R), consists of distributional analogues of power‐log functions with domain in R. This set contains the majority of the (one‐dimensional) distributions typically encountered in physics applications. In earlier work of the author it was shown that ??′(R) admits a closed convolution structure, provided that critical convolution products are defined by a functional extension process. In this paper, the general convolution product formula is derived. Convolution of AHDs on R is found to be associative, except for critical triple products. Critical products are shown to be non‐associative in a minimal and interesting way. Copyright © 2010 John Wiley & Sons, Ltd.     

Pluriassociative algebras II: The polydendriform operad and related operads

Dendriform algebras form a category of algebras recently introduced by Loday. A dendriform algebra is a vector space endowed with two nonassociative binary operations satisfying some relations. Any dendriform algebra is an algebra over the dendriform operad, the Koszul dual of the diassociative operad. We introduce here, by adopting the point of view and the tools offered by the theory of operads, a generalization on a nonnegative integer parameter γ of dendriform algebras, called γ-polydendriform algebras, so that 1-polydendriform algebras are dendriform algebras. For that, we consider the operads obtained as the Koszul duals of the γ-pluriassociative operads introduced by the author in a previous work. In the same manner as dendriform algebras are suitable devices to split associative operations into two parts, γ-polydendriform algebras seem adapted structures to split associative operations into 2γ operation so that some partial sums of these operations are associative. We provide a complete study of the γ-polydendriform operads, the underlying operads of the category of γ-polydendriform algebras. We exhibit several presentations by generators and relations, compute their Hilbert series, and construct free objects in the corresponding categories. We also provide consistent generalizations on a nonnegative integer parameter of the duplicial, triassociative and tridendriform operads, and of some operads of the operadic butterfly.     

Twist–Rotation Transformations of Binary Trees and Arithmetic Expressions

The paper studies the computational complexity and efficient algorithms for the twist–rotation transformations of binary trees, which is equivalent to the transformation of arithmetic expressions over an associative and commutative binary operation. The main results are (1) a full binary tree with n labeled leaves can be transformed into any other in at most 3n log n + 2n twist and rotation operations, (2) deciding the twist–rotation distance between two binary trees is NP-complete, and (3) the twist–rotation transformation can be approximated with ratio 6 log n + 4 in polynomial time for full binary trees with n uniquely labeled leaves.     

𝒪-Operators of Loday Algebras and Analogues of the Classical Yang–Baxter Equation

We introduce notions of 𝒪-operators of the Loday algebras including the dendriform algebras and quadri-algebras as a natural generalization of Rota–Baxter operators. The invertible 𝒪-operators give a sufficient and necessary condition on the existence of the 2 ⁿ⁺¹ operations on an algebra with the 2 ⁿ operations in an associative cluster. The analogues of the classical Yang–Baxter equation in these algebras can be understood as the 𝒪-operators associated to certain dual bimodules. As a byproduct, the constraint conditions (invariances) of nondegenerate bilinear forms on these algebras are given.     

Lie ideals of graded associative algebras

We study the Lie structure of graded associative algebras. Essentially, we analyze the relation between Lie and associative graded ideals, and between Lie and associative graded derivations. Gathering together results on both directions, we compute maximal graded algebras of quotients of graded Lie algebras that arise from associative algebras. We also show that the Lie algebra Der _gr (A) of graded derivations of a graded semiprime associative algebra is strongly non-degenerate (modulo a certain ideal containing the center of Der _gr (A)).     

An equational theory for trilattices

This paper presents the new algebra of trilattices, which are understood as the triadic generalization of lattices. As with lattices, there is an order-theoretic and an algebraic approach to trilattices. Order-theoretically, a trilattice is defined as a triordered set in which six triadic operations of some small arity exist. The Reduction Theorem guarantees that then also all finitary operations exist in trilattices. Algebraically, trilattices can be characterized by nine types of trilattice equations. Apart from the idempotent, associative, and commutative laws, further types of identities are needed such as bounds and limits laws, antiordinal, absorption, and separation laws. The similarities and differences between ordered and triordered sets, lattices and trilattices are discussed and illustrated by examples. Received May 26, 1998; accepted in final form May 7, 1999.     

Between associativity and commutativity

For any binary operation, four alternatives exist. It could be

1. (i) both commutative and associative;

2. (ii) neither commutative nor associative;

3. (iii) commutative but not associative;

4. (iv) associative but not commutative.

The basic arithmetical operations provide examples for the first two possibilities. This paper presents elementary examples for the last two possibilities. It is claimed that the study of these examples is extremely important in order to understand the logical independence of commutativity and associativity.     

Elimination of quantifiers for modules

Every first-order formula in the language ofR-modules (R an associative ring) is equivalent relative to the theory ofR-modules to a boolean combination of positive primitive formulas and ∀∃-sentence. Supported by Schweizerischer Nationalfonds.     

One-relator quotients of free products of cyclic groups

Abstract

The question of existence of n-ary systems playing the role of enveloping algebras for Filippov (n-Lie) algebras is investigated. We consider the ternary algebras whose reduced binary algebras are associative, the associative algebras, and two other classes of ternary algebras as possible enveloping algebras.     

Monoidal composition of distributions

Summary A useful property of a Poisson process is that if occurrences are independently selected with probability a, then the resulting process is Poisson with mean a, where is the original process mean. This property is examined from an abstract viewpoint under a natural restriction on the selection mechanism, namely that if a, b, characterize two selection mechanisms of interest, then the composite selection, when acting on a given distribution, is characterized by a o b, where o is an associative operation. In the terminology of Bourbaki, the quantities, a,b,..., together with o, form a monoid. The monoid will, for simplicity, be assumed to possess a two-sided unit e. The class of processes is generalized under a related closure restriction, which is that the distributions are members of a parametric family which is invariant under a monoidal selection mechanism. Various consequences of these assumptions are deduced, relating to the form of the selection mechanism and of the parametric families. The methods of Aczél are used here.Under the special assumption that the monoid involved is the multiplicative monoid of reals in the unit interval, that the selection is positively compatible with the parametric family, and that the generating functions are univariate and of Mandelbrojt type, it follows from the Bernstein-Widder Theorem that the distributions are mixtures of stuttering (also called compound) Poisson distributions. Moreover, it is shown that every parametric family is positively compatible with linear selection, and that negative binomial distributions are positively compatible with exponential selection.     

Arithmetical distributions and the sequential extension of binary relations

With the help of an iterative process, we define a fairly broad class of arithmetical distributions on which continuous operations of addition, multiplication, and differentiation are defined. The multiplication of arithmetical distributions that we introduce is made consistent with the known definitions of the product of distributions. The results obtained can be used to justify the passage to the limit in the study of nonlinear problems of mathematical physics. Formalizing our approach, we describe a construction of an extension of binary relations, which is called sequential extension, from a dense subset to the whole topological space. These results are extended to operations of the first order. We show that the sequential extension of differentiation from the set of infinitely differentiable functions to the set of distributions coincides up to isomorphism with the generalized differentiation of distributions. Translated fromMatematicheskie Zametki, Vol. 65, No. 6, pp. 836–853, June, 1999.     

Construction of vertex operator algebras from commutative associative algebras

Given a commutative associative algebra A with an associative form (’), we construct a vertex operator algebra V with the weight two space V₂;? A If in addition the form (’) is nondegenerate, we show that there is a simple vertex operator algebra with V₂;? A We also show that if A is semisimple, then the vertex operator algebra constructed is the tensor products of a certain number of Virasoro vertex operator algebras.     

On the Baxter functional equation

Summary A new shorter proof is given for the Theorem of P. Volkmann and H. Weigel determining the continuous solutionsf:R R of the Baxter functional equationf(f(x)y + f(y)x – xy) = f(x)f(y). The proof is based on the well known theorem of J. Aczél describing the continuous, associative, and cancellative binary operations on a real interval.     

Semilocal rings with <Emphasis Type="Italic">n</Emphasis>-Engel multiplicative group

An associative ring R with unit element is called semilocal if R modulo its Jacobson radical is an artinian ring. It is proved that the multiplicative group R* of a semilocal ring R generated by R* satisfies an n-Engel condition for some positive integer n if and only if R is m-Engel as a Lie ring for some positive integer m depending only on n.Received: 21 January 2003     

Non-Transitive Generalizations of Subdirect Products of Linearly Ordered Rings

Weakly associative lattice rings (wal-rings) are non-transitive generalizations of lattice ordered rings (l-rings). As is known, the class of l-rings which are subdirect products of linearly ordered rings (i.e. the class of f-rings) plays an important role in the theory of l-rings. In the paper, the classes of wal-rings representable as subdirect products of to-rings and ao-rings (both being non-transitive generalizations of the class of f-rings) are characterized and the class of wal-rings having lattice ordered positive cones is described. Moreover, lexicographic products of weakly associative lattice groups are also studied here.