Barrelled spaces and the open mapping theorem

1998 ◽  
Vol 41 (4) ◽  
pp. 473-477 ◽  
Author(s):  
Jürgen Müller ◽  
Jochen Wengenroth

AbstractWe present a short proof for a classical result on separating singularities of holomorphic functions. The proof is based on the open mapping theorem and the fusion lemma of Roth, which is a basic tool in complex approximation theory. The same method yields similar separation results for other classes of functions.


2016 ◽  
Vol 94 (1) ◽  
pp. 65-69
Author(s):  
SAAK S. GABRIYELYAN ◽  
SIDNEY A. MORRIS

It is proved that any surjective morphism $f:\mathbb{Z}^{{\it\kappa}}\rightarrow K$ onto a locally compact group $K$ is open for every cardinal ${\it\kappa}$. This answers a question posed by Hofmann and the second author.


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