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.
Gas is the most popular fuel line in domestic plumbing. Plumbers are responsible for gas line installation necessary for the household heating and cooking. Natural gas is carried at low pressure to your home via underground street pipes while propane gas is delivered from storage tanks located behind buildings or buried underground.