A local minimum for a function is a set of parameters for the function that is the smallest in a neighbourhood, that is f(p) < f(p+δ) for small changes $delta; in the parameter value. In a physical landscape this would correspond to the bottom of a small hole, but where there may be a much deeper gulf. It is the opposite of a local maximum and is to be contrasted with a global mimumum which is the smallest/lowest point overall.
Used on Chap. 4: pages 71, 75, 76; Chap. 9: page 185; Chap. 22: page 547
Also known as local minima