inverse,
adj. 1a. (of an element) related to a given element of a set on which an operation is defined in such a way that its product with the given element under that operation is the identity element, e. See also inverse matrix.
b. (as substantive) an inverse element. For example, the inverse of a function under composition is its inverse function; the additive inverse of x is -x, and the multiplicative inverse (or reciprocal) of x is 1/x. For non-commutative non-associative operations, an element, x, may have distinct left and right inverses, xl and xr respectively, such that xl x = e = x xr. 2. (of a relationship) relating two quantities in such a way that an increase in one corresponds to a decrease in the other and vice versa; thus speed is in inverse proportion to the time taken to cover a given distance. Compare direct. 3. (as substantive) another term for reciprocal.
b. (as substantive) an inverse element. For example, the inverse of a function under composition is its inverse function; the additive inverse of x is -x, and the multiplicative inverse (or reciprocal) of x is 1/x. For non-commutative non-associative operations, an element, x, may have distinct left and right inverses, xl and xr respectively, such that xl x = e = x xr. 2. (of a relationship) relating two quantities in such a way that an increase in one corresponds to a decrease in the other and vice versa; thus speed is in inverse proportion to the time taken to cover a given distance. Compare direct. 3. (as substantive) another term for reciprocal.