olemus
reaalvuline funktsioon \(f\), mille korral
\(f (ax + bx' ) \le a f (x ) + b f (x' )\), kus
\(x\) ja \(y\) on reaalarvud ning
\(a\) ja \(b\) on positiivsed reaalarvud, mille summa \(a + b = 1\)
= a continuous function whose value at the midpoint of every interval in its domain does not exceed the arithmetic mean of its values at the ends of the interval

näiteid
ruutfunktsioon \(f(x) = x^2\)

ülevaateid
http://mathworld.wolfram.com/ConvexFunction.html
https://en.wikipedia.org/wiki/Convex_function
https://web.stanford.edu/class/ee364a/lectures/functions.pdf
https://www.encyclopediaofmath.org/index.php/Convex_function_(of_a_real_variable)
https://www.encyclopediaofmath.org/index.php/Convex_function_(of_a_complex_variable)

vt ka
- kumer
- kumer hulk