Question

What is the name given to a statement that has been proven by deductive reasoning?

Answer 1

Deductive reasoning is consists of the axioms (or axiom schemata) and rules of inference that can be used to derive theorems of the system
Theorem is the name given to a statement that has been proven by deductive reasoning. The theorem is obtained with the rules of a deductive system on the basis of previously established statements, for example other theorems.