Quasi-reflection algebras and cyclotomic associators
Quasi-reflection algebras and cyclotomic associators
复制标题
准反射代数和分圆关联子
DOI:
10.1007/s00029-007-0048-2
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发表时间:
2004
期刊:
影响因子:
--
通讯作者:
B. Enriquez
中科院分区:
文献类型:
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作者:
B. Enriquez
Abstract.We develop a cyclotomic analogue of the theory of associators. Using a trigonometric version of the universal KZ equations, we prove the formality of a morphism
$$B_n^1 \rightarrow ({\mathbb{Z}}/N{\mathbb{Z}})^n \rtimes {\mathfrak{S}}_n$$
, where Bn1 is a braid group of type B. The formality isomorphism depends algebraically on a series ΨKZ, the “KZ pseudotwist”. We study the scheme of pseudotwists and show that it is a torsor under a group GTM(N, k), mapping to Drinfeld’s group GT(k), and whose Lie algebra is isomorphic to its associated graded
$$\mathfrak{grtm}$$
(N, k). We prove that Ihara’s subgroup GTK of the Grothendieck–Teichmüller group, defined using distribution relations, in fact coincides with it. We show that the subscheme of pseudotwists satisfying distribution relations is a subtorsor. We study the corresponding analogue
$$\mathfrak{grtmd}$$
(N, k) of
$$\mathfrak{grtm}$$
(N, k); it is a graded Lie algebra with an action of
$$({\mathbb{Z}}/N{\mathbb{Z}})^{\times}$$
, and we give a lower bound for the character of its space of generators.