On superquadracity

Research output: Contribution to journalArticlepeer-review


. There are two classes of functions called Superquadratic Functions. In some cases
these classes coincide but not always. In this paper this subject is discussed.
Our definition of a superquadratic function is: A function ϕ : [0.∞) → R is superquadratic
provided that for all x 0 there is a constant C(x) ∈ R such that
ϕ (y) ϕ (x) +C(x) (y−x) +ϕ (|y−x|)
for all y 0.
This definition was used in many papers since 2004.
On the other hand, Kominek and Troczka (2006) used W. Smajdor (1987) definition of
superquadracity, and in particular, for functions defined on R their definition is as follows:
The function ϕ : R → R is superquadratic if
ϕ (x+y) +ϕ (x−y) 2ϕ (x) +2ϕ (y),
is satisfied for all x,y ∈ R.
After discussing the differences and similarities of these definitions, we show that the class
of superquadratic functions as we defined, lead to many applications. Some of these applications
we show here
Original languageEnglish
Pages (from-to)329–339
JournalJournal of Mathematical Inequalities
StatePublished - 2009


Dive into the research topics of 'On superquadracity'. Together they form a unique fingerprint.

Cite this