Limit algebras of differential forms in non-commutative geometry

Research paper by S. J. Bhatt, A. Inoue

Indexed on: 26 Sep '08Published on: 26 Sep '08Published in: Proceedings - Mathematical Sciences

Abstract

Given a C*-normed algebra A which is either a Banach *-algebra or a Frechet *-algebra, we study the algebras Ω∞A and ΩεA obtained by taking respectively the projective limit and the inductive limit of Banach *-algebras obtained by completing the universal graded differential algebra Ω*A of abstract non-commutative differential forms over A. Various quantized integrals on Ω∞A induced by a K-cycle on A are considered. The GNS-representation of Ω∞A defined by a d-dimensional non-commutative volume integral on a d+-summable K-cycle on A is realized as the representation induced by the left action of A on Ω*A. This supplements the representation A on the space of forms discussed by Connes (Ch. VI.1, Prop. 5, p. 550 of [C]).