A convex combination of vectors in a real vector
space is a linear combination
whose coefficients satisfy and
. A subset
of a vector
space is convex if it contains every convex combination
of finitely many of its points. Equivalently,
is convex if
for all
and
.
The set of all convex combinations of points in is the convex hull of
. In particular, the convex combinations
of two distinct points
and
form the line segment joining
them.