Food pantries in Pima County Arizona and Tucson provide free or low cost groceries, food, and meals to families and individuals who need help.
One of the important aspects of REST (or at least HTTP) is the concept that some operations (verbs) are idempotent. As Gregor Roth said several years ago: The PUT method is idempotent. An idempotent method means that the result of a successful performed request is independent of the number of times it is executed. Idempotency is also something discussed in the SOA Design Patterns.
In algebra, an idempotent matrix is a matrix which, when multiplied by itself, yields itself. That is, the matrix M is idempotent if and only if MM = M. For this product MM to be defined, M must necessarily be a square matrix. Viewed this way, idempotent matrices are idempotent elements of matrix rings. 1 Example.