411 REFERENCE · Wikibooks
Mathematical Proof and the Principles of Mathematics/Logic/Rules of inference summary
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This is a list of the rules of inference given in previous sections. In the notation being used, a solid horizontal bar means that the statement below is a valid deduction from the statement(s) above. A vertical bar with a horizontal bar connected to it means that whatever is to the right of the vertical bar is a subproof, and whatever is above the horizontal bar are assumption(s) and whetever is below the horizontal bar is what has been derived. The names given are just placeholders and no guarantees are made that they are standard in any way.
Propositional logic
Rules not requiring subproofs
Iteration
Use of contradiction
Disjunction by first case
or
Disjunction by second case
or
First use of conjunction
and
Second use of conjunction
and
Implication from the conclusion
implies
Implication from false assumption
not implies
Double negation
not not
Equivalence to implication
iff implies
Equivalence to converse
iff implies
Conjunction by components
and
Use of disjunction, first alternative false
or not
Use of disjunction, second alternative false
or not
Use of implication, from premise (modus ponens)
implies
Use of implication, from false conclusion (modus tollens)
implies not not
Rules requiring one subproof
Implication by direct proof
implies