ABSTRACT
In 1925 Dirac published a paper building on Heisenberg’s sketchy outline of a mathematical structure for quantum theory. He followed this up in 1926 with a paper demonstrating how the Schrödinger and Heisenberg approaches were di erent ways of looking at the same basic mathematical picture. In essence, Dirac showed how basis states could be set up, how a state can be expanded over this basis, and how one basis can be converted into another equally valid description using a di erent basis.
