منابع مشابه
Hopf diagrams and quantum invariants
The Reshetikhin-Turaev invariant, Turaev’s TQFT, and many related constructions rely on the encoding of certain tangles (n-string links, or ribbon n-handles) as n-forms on the coend of a ribbon category. We introduce the monoidal category of Hopf diagrams, and describe a universal encoding of ribbon string links as Hopf diagrams. This universal encoding is an injective monoidal functor and admi...
متن کاملAxioms for Hopf Invariants
1. Since H. Hopf first proved that irziS) « Z by showing that a certain invariant was non tri vial, several similar invariants—called generalized Hopf invariants—have been described; indeed, there are no less than 6 different definitions in the literature, and it was not always clear whether theorems about one applied to others. Many definitions were riddled with choices which had to be made, a...
متن کاملInvariants of Hopf Algebras
In the winter of 1999 I gave a series of lectures at Queen’s university about some recent results concerning the Cohen-Macaulay property of invariants of Hopf algebras. Tony Geramita asked me to write up my notes for the Queen’s Papers, and I happily took up his suggestion. Although this article focuses on the proof of one main theorem (Theorem 2.11 on page 12), it has some of the character of ...
متن کاملInvariants of finite Hopf algebras
This paper extends classical results in the invariant theory of finite groups and finite group schemes to the actions of finite Hopf algebras on commutative rings. Suppose that H is a finite dimensional Hopf algebra and A a commutative algebra, say over a field K. Let δ : A → A ⊗H be an algebra homomorphism which makes A into a right H-comodule. In this case A is called an H-comodule algebra. T...
متن کاملInvolutory Hopf algebras and 3-manifold invariants
We establish a 3-manifold invariant for each finite-dimensional, involutory Hopf algebra. If the Hopf algebra is the group algebra of a group G, the invariant counts homomorphisms from the fundamental group of the manifold to G. The invariant can be viewed as a state model on a Heegaard diagram or a triangulation of the manifold. The computation of the invariant involves tensor products and con...
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ژورنال
عنوان ژورنال: Topology and its Applications
سال: 2015
ISSN: 0166-8641
DOI: 10.1016/j.topol.2015.09.045