Let A be a unital complex C
* algebra, L
*(A) the projective symmetric surgery groups, and K
*(A) topological K theory. We define groups B
*(A) of bordism classes of Fredholm complexes over A with Poincaré duality. These generalize the de Rham complex. It is shown that there are isomorphisms B
*(A)

K
* (A) and B
*(A)

L
*(A) given by abstract versions of the signature operator and symmetric signature. The remaining side of a triangle is formed by an isomorphism due to Mi


enko.
Signature operator - Wall groups - algebraic surgery - Fredholm complexes