Displaying similar documents to “Concerning the common boundary of two domains”

Concerning the sum of a countable number of mutually exclusive continua in the plane

R. Moore (1924)

Fundamenta Mathematicae

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In 1918 Sierpiński showed that if the sum of a countably infinite collection of closed point sets is bounded then it is not a continuum. He raised the question weather this theorem remains true if the restriction that the sum should be bounded is removed from the hypothesis. The purpose of the present paper is to show that for the case where each point set of the collection in question is itself a continuum, this question may be answered in the affirmative.

Concerning continuous curves

R. Wilder (1925)

Fundamenta Mathematicae

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The present paper has three main objects: 1. to study the analogy between ordinary two-dimensional space and a plane continuous curve; 2. to characterize and analyze the boundaries of the domains complementary to a plane continuous curve; 3. to give a new characterization of continuous curves suitable for any number of dimensions;

Closed connected sets which remain connected upon the removal of certain, connected subsets

John Kline (1924)

Fundamenta Mathematicae

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The purpose of this paper is to prove: Theorem: Suppose M is a closed connected set containing more than one point such that if g is any connected subset of M, then M-g is connected. Under these conditions M is a simple closed curve. Theorem: If M is an unbounded closed connected set which remains connected upon the removal of any unbounded connected proper subset, then M is either an open curve, a ray of an open curve or a simple closed curve J plus OP, a ray of an open curve which...