Research output: Contribution to journal › Article › peer-review
The Strong Continuity of Convex Functions. / Malozemov, V. N. ; Plotkin, A. V. ; Tamasyan, G. Sh. .
In: Vestnik St. Petersburg University: Mathematics, Vol. 51, No. 3, 04.09.2018, p. 244-248.Research output: Contribution to journal › Article › peer-review
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TY - JOUR
T1 - The Strong Continuity of Convex Functions
AU - Malozemov, V. N.
AU - Plotkin, A. V.
AU - Tamasyan, G. Sh.
N1 - Malozemov, V.N., Plotkin, A.V. & Tamasyan, G.S. The Strong Continuity of Convex Functions. Vestnik St.Petersb. Univ.Math. 51, 244–248 (2018). https://doi.org/10.3103/S1063454118030056
PY - 2018/9/4
Y1 - 2018/9/4
N2 - A convex function defined on an open convex set of a finite-dimensional space is known to be continuous at every point of this set. In fact, a convex function has a strengthened continuity property. The notion of strong continuity is introduced in this study to show that a convex function has this property. The proof is based on only the definition of convexity and Jensen’s inequality. The definition of strong continuity involves a constant (the constant of strong continuity). An unimprovable value of this constant is given in the case of convex functions. The constant of strong continuity depends, in particular, on the form of a norm introduced in the space of arguments of a convex function. The polyhedral norm is of particular interest. It is straightforward to calculate the constant of strong continuity when it is used. This requires a finite number of values of the convex function.
AB - A convex function defined on an open convex set of a finite-dimensional space is known to be continuous at every point of this set. In fact, a convex function has a strengthened continuity property. The notion of strong continuity is introduced in this study to show that a convex function has this property. The proof is based on only the definition of convexity and Jensen’s inequality. The definition of strong continuity involves a constant (the constant of strong continuity). An unimprovable value of this constant is given in the case of convex functions. The constant of strong continuity depends, in particular, on the form of a norm introduced in the space of arguments of a convex function. The polyhedral norm is of particular interest. It is straightforward to calculate the constant of strong continuity when it is used. This requires a finite number of values of the convex function.
KW - constant of strong continuity
KW - convex function
KW - strong continuity
UR - http://www.scopus.com/inward/record.url?scp=85052839845&partnerID=8YFLogxK
U2 - 10.3103/S1063454118030056
DO - 10.3103/S1063454118030056
M3 - Article
VL - 51
SP - 244
EP - 248
JO - Vestnik St. Petersburg University: Mathematics
JF - Vestnik St. Petersburg University: Mathematics
SN - 1063-4541
IS - 3
ER -
ID: 35369415