the earliest application of algebraic "k"-theory to topology was whitehead's construction of whitehead torsion. a closely related construction was found by c. t. c. wall in 1963. wall found that a space π dominated by a finite complex has a generalized euler characteristic taking values in a quotient of "k"(zπ), where π is the fundamental group of the space. this invariant is called "wall's finiteness obstruction" because "x" is homotopy equivalent to a finite complex if and only if the invariant vanishes. laurent siebenmann in his thesis found an invariant similar to wall's that gives an obstruction to an open manifold being the interior of a compact manifold with boundary. if two manifolds with boundary "m" and "n" have isomorphic interiors (in top, pl, or diff as appropriate), then the isomorphism between them defines an "h"-cobordism between "m" and "n".