Posted by Stephen Watson on December 15, 1997 at 15:44:13: In Reply to: a brief definition posted by Melanie Meyer on December 15, 1997 at 15:41:56: Dear Melanie, Thanks for your question. Stephen Barr in his 1964 book "Experiments in Topology" said "topology is curiously hard to define... (it) started as a kind of geometry but it has reached into many other mathematical fields." "In one sense it is the study of continuity: beginning with the continuity of space, or shapes, it generalizes and then by analogy leads into other kinds of continuity- and space as we usually understand it is left far behind.... A topologist is interested in those properties of a thing that while they are in a sense geometrical are the most permanent- the ones that will survive distortion and stretching." But modern topology goes much further than this: The great topologist Paul Alexandroff said in 1932: "The development of set-theoretic methods in topology first led to (the) discovery (of strange phenomena) and consequently, to a substantial extension of the idea of space. I would formulate the basic problem of set-theoretic topology as follows: to determine which set-theoretic structures have a connection with the intuitively given material of elementary polyhedral topology and hence deserve to be considered as geometrical figures- even if very general ones." I hope this helps a little. May we put your question (and my reply) in our "Ask a Topologist" feature? Professor Stephen Watson Department of Mathematics York University 4700 Keele St., North York, Ontario M3J1P3 CANADA