出典:Wikipedia
出典:『Wikipedia』 (2011/07/31 10:16 UTC 版)
In mathematics, the zero set of a real-valued function f : X → R (or more generally, a function taking values in some additive group) is the subset f − 1(0) of X (the inverse image of {0}). In other words, the zero set of the function f is the subset of X on which f(x) = 0. The cozero set of f is the complement of the zero set of f (i.e. the subset of X on which f is nonzero).