Multicoherence of spaces of the form 𝑋/𝑀

Author:

Illanes M. Alejandro

Abstract

Let X X be a connected, locally connected, normal T 1 {T_1} -space and let M M be a closed connected, locally connected subspace of X X . Suppose that X / M X/M denotes the space obtained by identifying M M in a single point, and that, for a connected space Y Y , ı ( Y ) \imath (Y) denotes the multicoherence degree of Y Y . In this paper, we prove that if M M is unicoherent, then ı ( X ) = ı ( X / M ) \imath (X) = \imath (X/M) . As an application of this result we prove that if X = A B X = A \cup B , where A , B A,B are closed subsets of X X and A B A \cap B is connected, locally connected and unicoherent, then ı ( X ) = ı ( A ) + ı ( B ) \imath (X) = \imath (A) + \imath (B) . Also, we prove that if X / M X/M is unicoherent, then ı ( X ) ı ( M ) \imath (X) \leqslant \imath (M) .

Publisher

American Mathematical Society (AMS)

Subject

Applied Mathematics,General Mathematics

Reference11 articles.

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