A Constructive Proof of Ky Fan's Generalization of Tucker's Lemma
arXiv:math/0310444
Abstract
We present a constructive proof of Ky Fan's combinatorial lemma concerning labellings of triangulated spheres. Our construction works for triangulations of that contain a flag of hemispheres. As a consequence, we produce a constructive proof of Tucker's lemma that holds for a larger class of triangulations than previous constructive proofs.
related work at http://www.math.hmc.edu/~su/papers.html