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Maximal ideals in the Lie algebra of vector fields

Jiří Vanžura (1988)

Commentationes Mathematicae Universitatis Carolinae

Measure and measurable functions of $S^{n}$

Angeliki Kontolatou (1994)

Acta Mathematica et Informatica Universitatis Ostraviensis

Minimal ideals and cancellation in ßN.

N. Hindman (1982)

Semigroup forum

More on tie-points and homeomorphism in ℕ*

Alan Dow, Saharon Shelah (2009)

Fundamenta Mathematicae

A point x is a (bow) tie-point of a space X if X∖x can be partitioned into (relatively) clopen sets each with x in its closure. We denote this as $X = A ⋈_{x} B$ where A, B are the closed sets which have a unique common accumulation point x. Tie-points have appeared in the construction of non-trivial autohomeomorphisms of βℕ = ℕ* (by Veličković and Shelah Steprans) and in the recent study (by Levy and Dow Techanie) of precisely 2-to-1 maps on ℕ*. In these cases the tie-points have been the unique fixed point...

More on $κ$ -Ohio completeness

D. Basile (2011)

Commentationes Mathematicae Universitatis Carolinae

We study closed subspaces of $κ$ -Ohio complete spaces and, for $κ$ uncountable cardinal, we prove a characterization for them. We then investigate the behaviour of products of $κ$ -Ohio complete spaces. We prove that, if the cardinal $κ^{+}$ is endowed with either the order or the discrete topology, the space ${(κ^{+})}^{κ^{+}}$ is not $κ$ -Ohio complete. As a consequence, we show that, if $κ$ is less than the first weakly inaccessible cardinal, then neither the space $ω^{κ^{+}}$ , nor the space $ℝ^{κ^{+}}$ is $κ$ -Ohio complete.

Mutually compactificable topological spaces.

Kovár, Martin Maria (2007)

International Journal of Mathematics and Mathematical Sciences