Jon Berrick National University of Singapore Intertwining matrices and K-theory Friday 15th, November 12:05-12:55pm, Carslaw 373. Higher algebraic K-theory was created by D. Quillen by applying certain topolog ical functors to the group of all invertible matrices over a given ring. This provi ded an important generalization of a group earlier constructed by J.H.C. Whitehead. However, it ignored the other historic foundation of K-theory, namely the ideal cla ss group of algebraic number theory. In this talk we show how (for commutative ring s) it is possible to overcome this defect by focusing attention on a novel class of matrices, which I call intertwining matrices.