Steve D'Aprano <steve+pyt...@pearwood.info> writes: > I've read a few people claim that disallowing multiplication from > standard arithmetic renders it weak enough that you can prove it > complete and correct, but since they give no proof or even evidence I > have my doubts.
That system is called Presburger arithmetic (see Wikipedia). It can be proved consistent by quantifier elimination but is not powerful enough to prove (or maybe even state) its own consistency. Surprisingly, there are also theories that can state and prove their own consistency: https://en.wikipedia.org/wiki/Self-verifying_theories -- https://mail.python.org/mailman/listinfo/python-list
