1) идемпотент 2) идемпотентный 3) идемпотентный элемент
adjective Etymology: Latin idem same + potent-, potens having power — more at potent relating to or being a mathematical quantity which when applied to itself under a given binary operation (as multiplication) equals itself; also relating to or being an operation under which a mathematical quantity is idempotent • idempotent noun
1. This term can be used to describe C header files, which contain common definitions and declarations to be included by several source files. If a header file is ever included twice during the same compilation (perhaps due to nested #include files), compilation errors can result unless the header file has protected itself against multiple inclusion; a header file so protected is said to be idempotent. 2. The term can also be used to describe an initialisation subroutine that is arranged to perform some critical action exactly once, even if the routine is called several times.