  First, dark matter is introduced. Next, the Dirac negative energy state is
rediscussed. It is a negative matter with some new characteristics, which are
mainly the gravitation each other, but the repulsion with all positive matter.
Such the positive and negative matters are two regions of topological
separation in general case, and the negative matter is invisible. It is the
simplest candidate of dark matter, and can explain some characteristics of the
dark matter and dark energy. Recent phantom on dark energy is namely a negative
matter. We propose that in quantum fluctuations the positive matter and
negative matter are created at the same time, and derive an inflation cosmos,
which is created from nothing. The Higgs mechanism is possibly a product of
positive and negative matter. Based on a basic axiom and the two foundational
principles of the negative matter, we research its predictions and possible
theoretical tests, in particular, the season effect. The negative matter should
be a necessary development of Dirac theory. Finally, we propose the three basic
laws of the negative matter. The existence of four matters on positive,
opposite, and negative, negative-opposite particles will form the most perfect
symmetrical world.
