Closure, an identity element, inverse elements, associative property, commutative property.
http://wiki.answers.com/Q/What_are_the_properties_...

The most basic kind of mathematical expression are arithmetic operations. Arithmetic operations consist of any combination of numbers with a mathematical operation, such as multiplication
http://www.ehow.com/info_8698419_mathematicalexpr...

Not sure if this falls under system design. Completely Fair Scheduler. (CFS)1]  Using Red Black trees to solve the problem of scheduling in the Linux kernel. [1] http://en.wikipedia.org
http://www.quora.com/DistributedSystems/Whatare...

The Sumerians had the first known mathematical
http://www.chacha.com/question/whatisthefirstc...
