Completion of an identifiable stage of maintenance such as removing an aircraft engine for repair or storage.

How could the flogger of urchins be otherwise than animated and joyous?

I put a bet on the winning horse.

Thus the set X⨯Y becomes a ring with these operations and it is called the product ring. The identity element of the product ring with respect to the addition is obviously (0,0) where 0 and 0 are identity elements of addition in the rings X and Y!, respectively.