====== OP: Arithmetic Operations======

**Definition:** The arithmetic operations belong to a family of functions which represent the operators known from arithmetic:\\   PLUS=addition, MINUS=subtraction, TIMES=multiplication, DIV=division, and POW=exponentiation. Also for time moments and intervals.\\   
OP also play a central role in the semantic representation of natural language concepts  explicitly or implicitly related to mathematical operations, like //per, on average, altogether, in total, etc.//