A new geometric
characterization is presented for a function convex of order n on an open interval,
distinct from the whole of R. We shall prove that if f : (a,b) → R with b < +∞, if α
is an arbitrarily fixed number, α ≧ b, and if F(x) denotes the ordinate of the point of
intersection in the x,y-plane between the vertical line x = α and the osculating
parabola of order n to the graph of f at the point (x,f(x)), then f is convex of order
n on (a,b) iff F is increasing thereon.
|