No CrossRef data available.
Published online by Cambridge University Press: 20 November 2018
Let X be any connected C.W. complex. Let Λ2X be the 2-fold symmetric product of X, the set of unordered pairs (not necessarily distinct) of elements of X. Let ΔX ⊂ X2 be the diagonal, and also (by a slight abuse of notation) let ΔX ⊂ Λ2X also denote the set of unordered pairs {x, x}.