The C*-algebraic formulation can be seen to include both classical and quantum systems.

In everyday language, this says that a quantum system will follow the line of least resistance from one state to another.

A separation principle also exists for the control of a quantum systems.

Past and future measurements, taken together, provide complete information about a quantum system.

The configuration space of a quantum mechanical system cannot be worked out without some physical knowledge.

All over the world measurements are continually being made on quantum mechanical systems.

For quantum systems it seems that once they have met there is never true parting.

This has been extended to much larger classes of quantum systems.

But with quantum systems, what you see is all you get.

Let A be an observable of a quantum mechanical system.