Biconditional elimination

Biconditional elimination
TypeRule of inference
FieldPropositional calculus
StatementIf is true, then one may infer that is true, and also that is true.
Symbolic statement

Biconditional elimination is the name of two valid rules of inference of propositional logic. It allows for one to infer a conditional from a biconditional. If is true, then one may infer that is true, and also that is true.[1] For example, if it's true that I'm breathing if and only if I'm alive, then it's true that if I'm breathing, I'm alive; likewise, it's true that if I'm alive, I'm breathing. The rules can be stated formally as:

and

where the rule is that wherever an instance of "" appears on a line of a proof, either "" or "" can be placed on a subsequent line.

  1. ^ Cohen, S. Marc. "Chapter 8: The Logic of Conditionals" (PDF). University of Washington. Archived (PDF) from the original on 2022-10-09. Retrieved 8 October 2013.