Enumeration of Nilpotent Loops via Cohomology
نویسنده
چکیده
The isomorphism problem for centrally nilpotent loops can be tackled by methods of cohomology. We develop tools based on cohomology and linear algebra that either lend themselves to direct count of the isomorphism classes (notably in the case of nilpotent loops of order 2q, q a prime), or lead to efficient classification computer programs. This allows us to enumerate all nilpotent loops of order less than 24.
منابع مشابه
Abelian Ideals and Cohomology of Symplectic Type
For symplectic Lie algebras sp(2n,C), denote by b and n its Borel subalgebra and maximal nilpotent subalgebra, respectively. We construct a relationship between the abelian ideals of b and the cohomology of n with trivial coefficients. By this relationship, we can enumerate the number of abelian ideals of b with certain dimension via the Poincaré polynomials of Weyl groups of type An−1 and Cn.
متن کاملOn continuous cohomology of locally compact Abelian groups and bilinear maps
Let $A$ be an abelian topological group and $B$ a trivial topological $A$-module. In this paper we define the second bilinear cohomology with a trivial coefficient. We show that every abelian group can be embedded in a central extension of abelian groups with bilinear cocycle. Also we show that in the category of locally compact abelian groups a central extension with a continuous section can b...
متن کاملOn the Structure of the Cohomology of Nilpotent Lie Algebras
The exterior algebra over the centre of a Lie algebra acts on the cohomology of the Lie algebra in a natural way. Focusing on nilpotent Lie algebras, we explore the module structure afforded by this action. We show that for all two-step nilpotent Lie algebras, this module structure is non-trivial, which partially answers a conjecture of Cairns and Jessup [4]. The presence of free submodules ind...
متن کاملFiltrations on Springer fiber cohomology and Kostka polynomials
We prove a conjecture which expresses the bigraded Poisson-de Rham homology of the nilpotent cone of a semisimple Lie algebra in terms of the generalized (one-variable) Kostka polynomials, via a formula suggested by Lusztig. This allows us to construct a canonical family of filtrations on the flag variety cohomology, and hence on irreducible representations of the Weyl group, whose Hilbert seri...
متن کاملCohomology Rings and Nilpotent Quotients of Real and Complex Arrangements
For an arrangement with complement X and fundamental group G, we relate the truncated cohomology ring, H≤2(X), to the second nilpotent quotient, G/G3. We define invariants of G/G3 by counting normal subgroups of a fixed prime index p, according to their abelianization. We show how to compute this distribution from the resonance varieties of the Orlik-Solomon algebra mod p. As an application, we...
متن کامل