Rule of Material Implication/Definition

From ProofWiki
Jump to navigation Jump to search

Theorem

The Rule of Material Implication can be used as a definition for the logical operator that is implication:

$p \implies q := \neg p \lor q$


Historical Note

This definition appears in the introductory material of 1910: Alfred North Whitehead and Bertrand Russell: Principia Mathematica: Volume 1, and some other authors follow their lead.


Sources