Let Q(α) and Q(β) be algebraic number fields. We describe a new method to find (if they exist) all isomorphisms, Q(β) → Q(α). The algorithm is particularly efficient if there is only one isomorphism.

We investigate the structure of the Medvedev lattice as a partial order. We prove that every interval in the lattice is either finite, in which case it is isomorphic to a finite Boolean algebra, or contains an antichain of size 2 א0 , the size of the lattice itself. We also prove that it is consistent that the lattice has chains of size 2 א0 , and in fact that these big chains occur in every in...

We exploit the Fedosov-Weinstein-Xu (FWX) resolution proposed in q-alg/9709043 to establish an isomorphism between the ring of Hochschild cohomology of the quantum algebra of functions on a symplectic manifold M and the ring H(M,C((~))) of De Rham cohomology of M with the coefficient field C((~)) without making use of any version of formality theorem. We also show that the Gerstenhaber bracket ...

Let [Formula: see text] be a text]-dimensional quantum polynomial algebra, and central regular element. The quotient algebra is called noncommutative conic. For conic text], there finite-dimensional which determines the singularity of text]. In this paper, we mainly focus on such that its quadratic dual commutative, equivalent to say, determined by symmetric superpotential. We classify these co...

Abstract We study the Modular Isomorphism Problem applying a combination of existing and new techniques. make use small group algebra to give positive answer for two classes groups nilpotency class 3. also introduce approach derive properties lower central series finite ????-group from structure associated modular algebra. Finally, we so-called ????-obelisks which are highlighted by recent comp...

Let An(k) be the Weyl algebra, with k a field of characteristic zero. It is known that every projective finitely generated left module is free or isomorphic to a left ideal. Let M be a left submodule of a free module. In this paper we give an algorithm to compute the projective dimension of M . If M is projective and rank(M) ≥ 2 we give a procedure to find a basis. © 2003 Elsevier Ltd. All righ...

The Grätzer-Schmidt theorem of lattice theory states that each algebraic lattice is isomorphic to the congruence lattice of an algebra. A lattice is algebraic if it is complete and generated by its compact elements. We show that the set of indices of computable lattices that are complete is Π 1 -complete; the set of indices of computable lattices that are algebraic is Π 1 -complete; and that th...

Usually we shall just call A an algebra if the field k is clear from the context. The algebra A is associative if multiplication is associative i.e. for all a, b, c ∈ A, (ab)c = a(bc), and unital if there is a multiplicative identity, i.e. an element usually denoted by 1 such that, for all a ∈ A, 1a = a1 = a. Note that, in this case, 1 = 0 ⇐⇒ A = {0}. Otherwise, the map k → A defined by t 7→ t·...

This paper relates skein spaces based on the Kauffman bracket and spin structures. A spin structure on an oriented 3-manifold provides an isomorphism between the skein space for parameter A and the skein space for parameter −A. There is an application to Penrose’s binor calculus, which is related to the tensor calculus of representations of SU(2). The perspective developed here is that this ten...

We consider the notion of an isomorphism between two hyper BCI-algebras and obtain all of the hyper BCI-algebras of order 3. It is shown that there exist 14 proper hyper BCI-algebras and 5 proper weak hyper BCI-algebras of order 3 up to isomorphism. Finally, further study on the theory of hyper BCI-algebra and its related hyper structure and applications of our results in information sciences a...