An immediate inference in which the proposition’s quality is changed and the predicate is replaced with its complement. (See also Categorical proposition, Complement, and Quality.) Obversion is valid for all…
In a formal system of logic, a principle whereby one statement is inferred from another or others; the logical rules by which validity is defined. https://youtube.com/shorts/IcuiD9lPVFg?feature=share
Knowledge that some proposition is true. https://youtube.com/shorts/_JqKePP_glU?feature=share