Conditionally δ-midconvex functions

Verfasser / Beitragende:
[Jacek Chudziak, Jacek Tabor, Józef Tabor]
Ort, Verlag, Jahr:
2015
Enthalten in:
Aequationes mathematicae, 89/4(2015-08-01), 981-990
Format:
Artikel (online)
ID: 605508852
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024 7 0 |a 10.1007/s00010-014-0304-4  |2 doi 
035 |a (NATIONALLICENCE)springer-10.1007/s00010-014-0304-4 
245 0 0 |a Conditionally δ-midconvex functions  |h [Elektronische Daten]  |c [Jacek Chudziak, Jacek Tabor, Józef Tabor] 
520 3 |a Let X be a real linear space, V be a nonempty subset of X and δ be a nonnegative real number. A function $${f : V \to \mathbb{R}}$$ f : V → R is said to be conditionally δ-midconvex provided $${f(\frac{x+y}{2}) \leq \frac{f(x) + f(y)}{2} + \delta}$$ f ( x + y 2 ) ≤ f ( x ) + f ( y ) 2 + δ for every $${x, y \in V}$$ x , y ∈ V such that $${\frac{x + y}{2} \in V}$$ x + y 2 ∈ V . We show that if V satisfies some reasonable assumptions, then for every bounded from above conditionally δ-midconvex function $${f : V \to \mathbb{R}}$$ f : V → R the following estimation holds: $${\sup f(V) \leq \sup f(ext \, V) + k (V)\delta}$$ sup f ( V ) ≤ sup f ( e x t V ) + k ( V ) δ , where ext V denotes the set of all extremal points of V and k(V) is a respective constant depending on V. 
540 |a The Author(s), 2014 
690 7 |a Midconvex function  |2 nationallicence 
690 7 |a approximately midconvex function  |2 nationallicence 
690 7 |a extremal point  |2 nationallicence 
700 1 |a Chudziak  |D Jacek  |u Faculty of Mathematics and Sciences, University of Rzeszów, ul.Prof. St. Pigonia 1, 35-310, Rzeszów, Poland  |4 aut 
700 1 |a Tabor  |D Jacek  |u Department of Mathematics and Computer Science, Jagiellonian University, Kraków, Poland  |4 aut 
700 1 |a Tabor  |D Józef  |u Faculty of Mathematics and Sciences, University of Rzeszów, ul.Prof. St. Pigonia 1, 35-310, Rzeszów, Poland  |4 aut 
773 0 |t Aequationes mathematicae  |d Springer Basel  |g 89/4(2015-08-01), 981-990  |x 0001-9054  |q 89:4<981  |1 2015  |2 89  |o 10 
856 4 0 |u https://doi.org/10.1007/s00010-014-0304-4  |q text/html  |z Onlinezugriff via DOI 
898 |a BK010053  |b XK010053  |c XK010000 
900 7 |a Metadata rights reserved  |b Springer special CC-BY-NC licence  |2 nationallicence 
908 |D 1  |a research-article  |2 jats 
949 |B NATIONALLICENCE  |F NATIONALLICENCE  |b NL-springer 
950 |B NATIONALLICENCE  |P 856  |E 40  |u https://doi.org/10.1007/s00010-014-0304-4  |q text/html  |z Onlinezugriff via DOI 
950 |B NATIONALLICENCE  |P 700  |E 1-  |a Chudziak  |D Jacek  |u Faculty of Mathematics and Sciences, University of Rzeszów, ul.Prof. St. Pigonia 1, 35-310, Rzeszów, Poland  |4 aut 
950 |B NATIONALLICENCE  |P 700  |E 1-  |a Tabor  |D Jacek  |u Department of Mathematics and Computer Science, Jagiellonian University, Kraków, Poland  |4 aut 
950 |B NATIONALLICENCE  |P 700  |E 1-  |a Tabor  |D Józef  |u Faculty of Mathematics and Sciences, University of Rzeszów, ul.Prof. St. Pigonia 1, 35-310, Rzeszów, Poland  |4 aut 
950 |B NATIONALLICENCE  |P 773  |E 0-  |t Aequationes mathematicae  |d Springer Basel  |g 89/4(2015-08-01), 981-990  |x 0001-9054  |q 89:4<981  |1 2015  |2 89  |o 10