Semiperfect and coreflexive coalgebras

Autor: Dascalescu, Sorin, Iovanov, Miodrag C.
Rok vydání: 2015
Předmět:
Zdroj: Forum Math. 27 (2015), No. 5, 2587--2608
Druh dokumentu: Working Paper
Popis: We study non-counital coalgebras and their dual non-unital algebras, and introduce the finite dual of a non-unital algebra. We show that a theory that parallels in good part the duality in the unital case can be constructed. Using this, we introduce a new notion of left coreflexivity for counital coalgebras, namely, a coalgebra is left coreflexive if $C$ is isomorphic canonically to the finite dual of its left rational dual $Rat(_{C^*}C^*)$. We show that right semiperfectness for coalgebras is in fact essentially equivalent to this left reflexivity condition, and we give the connection to usual coreflexivity. As application, we give a generalization of some recent results connecting dual objects such as quiver or incidence algebras and coalgebras, and show that Hopf algebras with non-zero integrals (compact quantum groups) are coreflexive.
Comment: 14pp; published version 22pp
Databáze: arXiv