Following [3] we confirm a conjecture of Yde Venema by piecing together results from various authors. Specifically, we show that if A is a residually finite, finitely generated modal algebra such that HSP(A) has equationally definable principal congruences, then the profinite completion of A is the MacNeille completion of A, and ♦ is smooth. Specific examples of such modal algebras are the free...

We establish an isomorphism between the space of logarithmic intertwining operators among suitable generalized modules for a vertex operator algebra and the space of homomorphisms between suitable modules for a generalization of Zhu’s algebra given by Dong-Li-Mason.

The L∞-algebra controlling simultaneous deformations of a morphism of associative algebras and its domain and codomain is described. Isomorphism of the cohomology of this L∞-algebra with the classical construction is shown.

We extend our work in [1] to the case of Hopf comodule coalgebras. We introduce the cocylindrical module C♮H, where H is a Hopf algebra with bijective antipode and C is a Hopf comodule coalgebra over H. We show that there exists an isomorphism between the cocyclic module of the crossed coproduct coalgebra C>◭H and ∆(C♮H), the cocyclic module related to the diagonal of C♮H. We approximate HC(C >...

In present work we consider C∗-algebras C∗(Af ) associated with simple unimodal nonbijective dynamical system (f,R) with special requirements. In the case when f is polynomial, Af = C〈X,X∗| XX∗ = f(X∗X)〉 and C∗(Af ) is its enveloping C∗-algebra. As typical examples we consider one-parameter family fμ(x) = μx(1 − x) and two-parameter family called Unharmonic Quantum Oscillator fp,q(x) = 1+ px− q...

For a commutative algebra A over C, denote g=Der(A). module the smash product A#U(g) is called jet g-module, where U(g) universal enveloping of g. In present paper, we study modules in case A=C[t1±1,t2]. We show that A#U(g)≅D⊗U(L), D Weyl C[t1±1,t2,∂∂t1,∂∂t2], and L Lie subalgebra corresponding to Using isomorphism θ:L→m1,0Δ, m1,0Δ vector fields vanishing at point (1, 0), any irreducible finite...

The “character values” of the irreducible projective representations of Sk, the symmetric group of degree k, were determined by I. Schur using Schur’sQ-functions, which are indexed by the distinct partitions of k, [10], in a way analogous to Frobenius’ formula for the character values of the ordinary irreducible representations of Sk [2]. Behind Frobenius’ formula exists a duality relation of S...

For every algebraically closed field k of characteristic different from 2, we prove the following: (1) Generic finite dimensional (not necessarily associative) kalgebras of a fixed dimension, considered up to isomorphism, are parametrized by the values of a tuple of algebraically independent over k rational functions in the structure constants. (2) There exists an “algebraic normal form”, to wh...

For a prime p let G be a finite p-group and K a field of characteristic p. The Modular Isomorphism Problem (MIP) asks whether the modular group algebra KG determines the isomorphism type of G. We briefly survey the history of this problem and report on our computer-aided verification of the Modular Isomorphism Problem for the groups of order 512 and the field K with 2 elements.

I exhibit a pair of non-symmetric operads that, while not themselves isomorphic, induce isomorphic monads. The existence of such a pair implies that if ‘algebraic theory’ is understood as meaning ‘monad’ then operads cannot be regarded as algebraic theories of a special kind.