Axiom is  a general purpose Computer Algebra system. It is useful for research and development of mathematical algorithms. It defines a strongly typed, mathematically correct type hierarchy. It has a programming language and a built-in compiler.
Polybutylene is simply a type of plumbing material that was manufactured between the late 70's and early 90's. It is thought that it was installed in over 6 million homes during that time period.
Removing a hose bibb vacuum breaker sounds like a complicated plumbing procedure, but in fact it's as easy as removing a garden hose from your outdoor faucet. The vacuum breaker, which is required in some municipalities, screws onto to your faucet and prevents water from flowing backward from your hose into the water supply. It protects drinking water from contamination caused by dirt, chemicals or bacteria that could be sucked through the hose if the water pressure were to drop.