The symbolic language created by Peano plays a very grand rôle in these new researches.
Dedekind and Peano have worked out such ordinal theories of the number concept.
All these, however, are a concession, and are swept away by Professor Peano.
M. Couturat begins by stating Peano's five assumptions, which are independent, as has been proved by Peano and Padoa.
This method is due partly to Peano, partly to another Italian named Fano.
Two hundred years ago, Leibniz foresaw the science which Peano has perfected, and endeavoured to create it.