Displaying similar documents to “Some 2-point sets”

Integral formula for secantoptics and its application

Witold Mozgawa, Magdalena Skrzypiec (2012)

Annales Universitatis Mariae Curie-Sklodowska, sectio A – Mathematica

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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. ...

One Erdös style inequality

Tomáš J. Kepka, Petr C. Němec (2019)

Commentationes Mathematicae Universitatis Carolinae

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One unusual inequality is examined.

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

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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. ...

MetaPost Definitions

Taco Hoekwater (2020)

Zpravodaj Československého sdružení uživatelů TeXu

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The paper presents all syntactic rules for definitions in MetaPost. It contains many good and bad examples of definitions.

The union of two D-spaces need not be D

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

Fundamenta Mathematicae

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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.

Estimation of the noncentrality matrix of a noncentral Wishart distribution with unit scale matrix. A matrix generalization of Leung's domination result.

Heinz Neudecker (2004)

SORT

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The main aim is to estimate the noncentrality matrix of a noncentral Wishart distribution. The method used is Leung's but generalized to a matrix loss function. Parallelly Leung's scalar noncentral Wishart identity is generalized to become a matrix identity. The concept of Löwner partial ordering of symmetric matrices is used.

The Lvov years of Wacław Sierpiński

Andrzej Schinzel (2009)

Banach Center Publications

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

Some questions of Arhangel'skii on rotoids

Harold Bennett, Dennis Burke, David Lutzer (2012)

Fundamenta Mathematicae

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A rotoid is a space X with a special point e ∈ X and a homeomorphism F: X² → X² having F(x,x) = (x,e) and F(e,x) = (e,x) for every x ∈ X. If any point of X can be used as the point e, then X is called a strong rotoid. We study some general properties of rotoids and prove that the Sorgenfrey line is a strong rotoid, thereby answering several questions posed by A. V. Arhangel'skii, and we pose further questions.

Fat P-sets in the Space ω*

Ryszard Frankiewicz, Magdalena Grzech, Paweł Zbierski (2005)

Bulletin of the Polish Academy of Sciences. Mathematics

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We prove that-consistently-in the space ω* there are no P-sets with the ℂ-cc and any two fat P-sets with the ℂ⁺-cc are coabsolute.