The search session has expired. Please query the service again.

Displaying similar documents to “Some questions of Arhangel'skii on rotoids”

Some 2-point sets

James H. Schmerl (2010)

Fundamenta Mathematicae

Similarity:

Chad, Knight & Suabedissen [Fund. Math. 203 (2009)] recently proved, assuming CH, that there is a 2-point set included in the union of countably many concentric circles. This result is obtained here without any additional set-theoretic hypotheses.

Integral formula for secantoptics and its application

Witold Mozgawa, Magdalena Skrzypiec (2012)

Annales Universitatis Mariae Curie-Sklodowska, sectio A – Mathematica

Similarity:

Some properties of secantoptics of ovals defined by Skrzypiec in 2008 were proved by Mozgawa and Skrzypiec in 2009. In this paper we generalize to this case results obtained by Cieslak, Miernowski and Mozgawa in 1996 and derive an integral formula for an annulus bounded by a given oval and its secantoptic. We describe the change of the area bounded by a secantoptic and find the differential equation for this function. We finish with some examples illustrating the above results. ...

Integral formula for secantoptics and its application

Witold Mozgawa, Magdalena Skrzypiec (2012)

Annales UMCS, Mathematica

Similarity:

Some properties of secantoptics of ovals defined by Skrzypiec in 2008 were proved by Mozgawa and Skrzypiec in 2009. In this paper we generalize to this case results obtained by Cieślak, Miernowski and Mozgawa in 1996 and derive an integral formula for an annulus bounded by a given oval and its secantoptic. We describe the change of the area bounded by a secantoptic and find the differential equation for this function. We finish with some examples illustrating the above results. ...

Topological compactifications

Benjamin Vejnar (2011)

Fundamenta Mathematicae

Similarity:

We study those compactifications of a space such that every autohomeomorphism of the space can be continuously extended over the compactification. These are called H-compactifications. Van Douwen proved that there are exactly three H-compactifications of the real line. We prove that there exist only two H-compactifications of Euclidean spaces of higher dimension. Next we show that there are 26 H-compactifications of a countable sum of real lines and 11 H-compactifications of a countable...

The union of two D-spaces need not be D

Dániel T. Soukup, Paul J. Szeptycki (2013)

Fundamenta Mathematicae

Similarity:

We construct from ⋄ a T₂ example of a hereditarily Lindelöf space X that is not a D-space but is the union of two subspaces both of which are D-spaces. This answers a question of Arhangel'skii.

PROBLEMS

M. Chrobak, M. Habib, P. John, H. Sachs, H. Zernitz, J. R. Reay, G. Sierksma, M. M. Sysło, T. Traczyk, W. Wessel (1987)

Applicationes Mathematicae

Similarity:

A proof of the birationality of certain BHK-mirrors

Patrick Clarke (2014)

Complex Manifolds

Similarity:

We generalize and give an elementary proof of Kelly’s refinement [9] of Shoemaker’s result [11] on the birationality of certain BHK-mirrors. Our approach uses a construction that is equivalent to the Krawitz generalization [10] of the duality in Berglund-Hübsch [2].

The Lvov years of Wacław Sierpiński

Andrzej Schinzel (2009)

Banach Center Publications

Similarity:

An account is given of Sierpiński's activity in Lvov (1908-1918) interrupted by World War I.