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A generalization of Čech-complete spaces and Lindelöf Σ -spaces

Aleksander V. Arhangel'skii (2013)

Commentationes Mathematicae Universitatis Carolinae

The class of s -spaces is studied in detail. It includes, in particular, all Čech-complete spaces, Lindelöf p -spaces, metrizable spaces with the weight 2 ω , but countable non-metrizable spaces and some metrizable spaces are not in it. It is shown that s -spaces are in a duality with Lindelöf Σ -spaces: X is an s -space if and only if some (every) remainder of X in a compactification is a Lindelöf Σ -space [Arhangel’skii A.V., Remainders of metrizable and close to metrizable spaces, Fund. Math. 220 (2013),...

A generalization of Magill's Theorem for non-locally compact spaces

Gary D. Faulkner, Maria Cristina Vipera (1995)

Commentationes Mathematicae Universitatis Carolinae

In the theory of compactifications, Magill's theorem that the continuous image of a remainder of a space is again a remainder is one of the most important theorems in the field. It is somewhat unfortunate that the theorem holds only in locally compact spaces. In fact, if all continuous images of a remainder are again remainders, then the space must be locally compact. This paper is a modification of Magill's result to more general spaces. This of course requires restrictions on the nature of the...

A generalization of normal spaces

V. Renuka Devi, D. Sivaraj (2008)

Archivum Mathematicum

A new class of spaces which contains the class of all normal spaces is defined and its characterization and properties are discussed.

A generalization of semiflows on monomials

Hamid Kulosman, Alica Miller (2012)

Mathematica Bohemica

Let K be a field, A = K [ X 1 , , X n ] and 𝕄 the set of monomials of A . It is well known that the set of monomial ideals of A is in a bijective correspondence with the set of all subsemiflows of the 𝕄 -semiflow 𝕄 . We generalize this to the case of term ideals of A = R [ X 1 , , X n ] , where R is a commutative Noetherian ring. A term ideal of A is an ideal of A generated by a family of terms c X 1 μ 1 X n μ n , where c R and μ 1 , , μ n are integers 0 .

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