On $C^{\ast }$-algebras associated with $C^{\ast }$-correspondences

We study $C^{\ast }$-algebras arising from $C^{\ast }$-correspondences, which was introduced by the author. We prove the gauge-invariant uniqueness theorem, and obtain conditions for our $C^{\ast }$-algebras to be nuclear, exact, or satisfy the Universal Coefficient Theorem. We also obtain a 6-term exact sequence of $K$-groups involving the $K$-groups of our $C^{\ast }$-algebras.