Add a new page:
This is an old revision of the document!
CPT symmetry means that a mirror-image of our universe where we reverse all momenta (corresponding to the reversal of time) and with all matter replaced by anti-matter would evolve under exactly the same physical laws.
A nice introduction is this video by Veritasium.
According to the famous CPT theorem the symmetry CPT holds for all physical phenomena under quite reasonable assumptions.