Hi, everyone: I am trying to understand the intersection form, and I am having trouble with the notation used in Wikipedia's entry on intersection theory: http://en.wikipedia.org/wiki/Intersection_theory_(mathematics) Now, I am somewhat weak in my cohomology, and I understand the concept is necessarily involved, but I would appreciate some comments/insights on this: Specifically, in the definition of the bilinear form Qm, on the n-th cohomology ring H^n(M) : Qm: H^n(M,delM,Z) x H^n(M, delM; Z)-->Z , given by: Qm(a,b)=< a\/b, [M] > where '\/' is the cup product, 'del' is the boundary, and 'Z' are the integers. Now: What is this bracket operation < , > ?. It is not stated that M is Riemannian so I don't see how this would be an inner product. And, what is [M] here ? I have been reading up in H&Y (Hocking and Young) , and they are using different notation. Thanks for Any Help.