News & Events

Seminar

Date/Time:
Monday, December 23, 2019 - 14:30 to 15:30
Venue:
Mathematics Seminar Room
Speaker:
Amit Kumar
Affiliation:
NISER
Title:
Partial isometries in absolute matrix order unit spaces

In this talk, we shall introduce the notions of absolutely matrix ordered spaces and absolute matrix order unit spaces in the context of matrix ordered spaces. We shall prove that a unital, bijective $\ast$-linear map between absolute matrix order unit spaces is a complete isometry if, and only if, it is a completely absolute value preserving. From here, we deduce that on (unital) C$^*$-algebras such maps are precisely C$^*$-algebra isomorphisms. We shall extend the notion of orthogonality to the general elements of an absolute matrix order unit space and relate it to the orthogonality among positive elements. We shall introduce the notion of a partial isometry in an absolute matrix order unit space to describe the comparison of order projections. We shall also discuss direct limit of absolute matrix order unit spaces to show the existence of Grothendieck group" through order projections and prove that Grothendieck group" is a functor from category of absolute matrix order unit spaces with morphisms as unital completely absolute preserving maps" to category of abelian groups". Later, we define orthogonality of complete absolute preserving maps and prove that Grothendieck group" functor is additive on orthogonal unital completely absolute preserving maps.