• Topological *-algebras withC*-enveloping algebras II

• # Fulltext

https://www.ias.ac.in/article/fulltext/pmsc/111/01/0065-0094

• # Keywords

Frechet *-algebra; topological *-algebra; C*-enveloping algebra; unbounded operator representation; O*-algebra; smooth Frechet algebra crossed product; Pedersen ideal of aC*-algebra; groupoidC*-algebra; universal algebra on generators with relatio

• # Abstract

UniversalC*-algebrasC*(A) exist for certain topological *-algebras called algebras with aC*-enveloping algebra. A Frechet *-algebraA has aC*-enveloping algebra if and only if every operator representation ofA mapsA into bounded operators. This is proved by showing that every unbounded operator representation π, continuous in the uniform topology, of a topological *-algebraA, which is an inverse limit of Banach *-algebras, is a direct sum of bounded operator representations, thereby factoring through the enveloping pro-C*-algebraE(A) ofA. Given aC*-dynamical system (G,A,α), any topological *-algebraB containingCc(G,A) as a dense *-subalgebra and contained in the crossed productC*-algebraC*(G,A,α) satisfiesE(B) =C*(G,A,α). IfG = ℝ, ifB is an α-invariant dense Frechet *-subalgebra ofA such thatE(B) =A, and if the action α onB ism-tempered, smooth and by continuous *-automorphisms: then the smooth Schwartz crossed productS(ℝ,B,α) satisfiesE(S(ℝ,B,α)) =C*(ℝ,A,α). WhenG is a Lie group, theC-elementsC(A), the analytic elementsCω(A) as well as the entire analytic elementsCє(A) carry natural topologies making them algebras with aC*-enveloping algebra. Given a non-unitalC*-algebraA, an inductive system of idealsIα is constructed satisfyingA =C*-ind limIα; and the locally convex inductive limit ind limIα is anm-convex algebra with theC*-enveloping algebraA and containing the Pedersen idealKa ofA. Given generatorsG with weakly Banach admissible relationsR, we construct universal topological *-algebraA(G, R) and show that it has aC*-enveloping algebra if and only if (G, R) isC*-admissible.

• # Author Affiliations

1. Department of Mathematics, Sardar Patel University, Vallabh Vidyanagar - 388 120, India

• # Proceedings – Mathematical Sciences

Volume 130, 2020
All articles
Continuous Article Publishing mode

• # Editorial Note on Continuous Article Publication

Posted on July 25, 2019