The method of mathematics

Dear All, Is the method of mathematics a discipline in the Kantian sense of containing deviation [with ‘do not’] from rule (in addition to being confined to rule with definition)? For example, in studying the definition of function I, in addition to drawing an internal diagram with an arrow from every dot in domain to a dot in codomain, do not draw more than one arrow from any dot in the domain. But the problem with attending to ‘do not’ is a problem of enumerating error(s). I’d appreciate very much any corrections and clarifications that you, your time permitting, could provide. Thank you, posina [For admin and other information see: http://www.mta.ca/~cat-dist/ ]