Resumen de Cancellation of 3-Point Topological Spaces

Sheila Ivonne Carter, F. J. Craveiro de Carvalho

• The cancellation problem, which goes back to S. Ulam, is formulated as follows: Given topological spaces X, Y, Z, under what circumstances does X × Z ≈Y × Z (≈ meaning homeomorphic to) imply X ≈ Y ? In it is proved that, for T0 topological spaces and denoting by S the Sierpinski space, if X × S≈Y × S then X≈Y. This note concerns all nine (up to homeomorphism) 3-point spaces, which are given in.