formal logic

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun The study of the properties of propositions and deductive reasoning by abstraction and analysis of the form rather than the content of propositions under consideration.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun logic Mathematical logic.
• noun logic A particular logical calculus.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun any logical system that abstracts the form of statements away from their content in order to establish abstract criteria of consistency and validity