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- From: bubai@matt.ksu.ksu.edu (P. Chatterjee)
- Newsgroups: sci.math
- Subject: Need some help with Topology
- Date: 12 Dec 1992 02:15:46 -0600
- Organization: Kansas State University
- Lines: 22
- Message-ID: <1gc73iINNl4g@matt.ksu.ksu.edu>
- NNTP-Posting-Host: matt.ksu.ksu.edu
-
- I had a few questions (none homework, though!) and would appreciate any
- kind of help from the math-knowledgeables on the net.
-
-
- a) What does it mean to say that a set A is 'infinite'? 'Finiteness', by
- definition, implies that A is equivalent to a portion of the set of
- positive integers. Can this definition of 'finiteness' be used to
- motivate one for 'infiniteness'?
-
- b) Show that A is OPEN <==> X \ A is closed.
- Isn't this a definition or can it be proven?
-
- c) If A is infinite and p in A, show that A \ {p} is equivalent to A.
-
-
- d) Show that (A')' is a subset of A'.
-
- I'm studying for an exam and these conceptual glitches need to be clarified
- before I plunge into it.
-
-
- Thanks for all the help.
-