Conditional Proof - Occidental College
sites.oxy.edu › chapter6 › conditional-proofWe do that by using one of twospecial rules, the rule of conditional proofor the rule ofindirectproof. The rule, Conditional Proof (CP) is used when we want to derive aconditional. We begin using the rule by introducing an assumption, whichis the antecedent of the conditional we wish to derive. We then proceed"normally", that is, using our rules of inference and equivalencerules, until we derive the consequent of the desired conditional.
Fitch Proof Constructor - GitHub Pages
mrieppel.github.io/fitchjsNOTE: the order in which rule lines are cited is important for multi-line rules. For example, in an application of conditional elimination with citation "j,k →E", line j must be the conditional, and line k must be its antecedent, even if line k actually precedes line j in the proof. The only multi-line rules which are set up so that order doesn't matter are &I and ⊥I.
Natural deduction proof editor and checker
proofs.openlogicproject.orgFor the conditional you may use any of the symbols: → ⇒ ⊃ -> > For the universal quantifier (FOL only), you may use any of the symbols: ∀x (∀x) Ax (Ax) (x) ⋀x; For the existential quantifier (FOL only), you may use any of the symbols: ∃x (∃x) Ex (Ex) ⋁x; For a contradiction you may use any of the symbols: ⊥ XX #