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| Type | Label | Description |
|---|---|---|
| Statement | ||
| Theorem | mpand 701 | A deduction based on modus ponens. |
| Theorem | mpan2d 702 | A deduction based on modus ponens. |
| Theorem | mp2and 703 | A deduction based on modus ponens. |
| Theorem | mpdan 704 | An inference based on modus ponens. |
| Theorem | mpancom 705 | An inference based on modus ponens with commutation of antecedents. |
| Theorem | mpanl1 706 | An inference based on modus ponens. |
| Theorem | mpanl2 707 | An inference based on modus ponens. |
| Theorem | mpanl12 708 | An inference based on modus ponens. |
| Theorem | mpanr1 709 | An inference based on modus ponens. |
| Theorem | mpanr2 710 | An inference based on modus ponens. |
| Theorem | mpanlr1 711 | An inference based on modus ponens. |
| Theorem | mtt 712 | Modus-tollens-like theorem. |
| Theorem | mt2bi 713 | A false consequent falsifies an antecedent. |
| Theorem | mtbid 714 | A deduction from a biconditional, similar to modus tollens. |
| Theorem | mtbird 715 | A deduction from a biconditional, similar to modus tollens. |
| Theorem | mtbii 716 | An inference from a biconditional, similar to modus tollens. |
| Theorem | mtbiri 717 | An inference from a biconditional, similar to modus tollens. |
| Theorem | 2th 718 | Two truths are equivalent. |
| Theorem | 2false 719 | Two falsehoods are equivalent. |
| Theorem | tbt 720 | A wff is equivalent to its equivalence with truth. (The proof was shortened by Juha Arpiainen, 19-Jan-2006.) |
| Theorem | nbn2 721 | The negation of a wff is equivalent to the wff's equivalence to falsehood. (Contributed by Juha Arpiainen, 19-Jan-2006.) |
| Theorem | nbn 722 | The negation of a wff is equivalent to the wff's equivalence to falsehood. |
| Theorem | nbn3 723 | Transfer falsehood via equivalence. |
| Theorem | biantru 724 | A wff is equivalent to its conjunction with truth. |
| Theorem | biantrur 725 | A wff is equivalent to its conjunction with truth. |
| Theorem | biantrud 726 | A wff is equivalent to its conjunction with truth. |
| Theorem | biantrurd 727 | A wff is equivalent to its conjunction with truth. |
| Theorem | mpbiran 728 | Detach truth from conjunction in biconditional. |
| Theorem | mpbiran2 729 | Detach truth from conjunction in biconditional. |
| Theorem | mpbir2an 730 | Detach a conjunction of truths in a biconditional. |
| Theorem | biimt 731 | A wff is equivalent to itself with true antecedent. |
| Theorem | pm5.5 732 | Theorem *5.5 of [WhiteheadRussell] p. 125. |
| Theorem | pm5.62 733 | Theorem *5.62 of [WhiteheadRussell] p. 125. (Contributed by Roy F. Longton, 21-Jun-2005.) |
| Theorem | biort 734 | A wff is disjoined with truth is true. |
| Theorem | biorf 735 | A wff is equivalent to its disjunction with falsehood. Theorem *4.74 of [WhiteheadRussell] p. 121. |
| Theorem | biorfi 736 | A wff is equivalent to its disjunction with falsehood. |
| Theorem | bianfi 737 | A wff conjoined with falsehood is false. |
| Theorem | bianfd 738 | A wff conjoined with falsehood is false. |
| Theorem | pm4.82 739 | Theorem *4.82 of [WhiteheadRussell] p. 122. |
| Theorem | pm4.83 740 | Theorem *4.83 of [WhiteheadRussell] p. 122. |
| Theorem | pclem6 741 | Negation inferred from embedded conjunct. |
| Theorem | biantr 742 | A transitive law of equivalence. Compare Theorem *4.22 of [WhiteheadRussell] p. 117. |
| Theorem | orbidi 743 | Disjunction distributes over the biconditional. An axiom of system DS in Vladimir Lifschitz, "On calculational proofs" (1998), http://citeseer.ist.psu.edu/lifschitz98calculational.html. |
| Theorem | biass 744 | Associative law for the biconditional. An axiom of system DS in Vladimir Lifschitz, "On calculational proofs" (1998), http://citeseer.ist.psu.edu/lifschitz98calculational.html. Interestingly, this law was not included in Principia Mathematica but was apparently first noted by Jan Lukasiewicz circa 1923. (The proof was shortened by Juha Arpiainen, 19-Jan-2006.) |
| Theorem | biluk 745 | Lukasiewicz's shortest axiom for equivalential calculus. Storrs McCall, ed., Polish Logic 1920-1939 (Oxford, 1967), p. 96. |
| Theorem | pm5.7 746 | Disjunction distributes over the biconditional. Theorem *5.7 of [WhiteheadRussell] p. 125. This theorem is similar to orbidi 743. (Contributed by Roy F. Longton, 21-Jun-2005.) |
| Theorem | bigolden 747 | Dijkstra-Scholten's Golden Rule for calculational proofs. |
| Theorem | pm5.71 748 | Theorem *5.71 of [WhiteheadRussell] p. 125. (Contributed by Roy F. Longton, 23-Jun-2005.) |
| Theorem | pm5.75 749 | Theorem *5.75 of [WhiteheadRussell] p. 126. |
| Theorem | bimsc1 750 | Removal of conjunct from one side of an equivalence. |
| Theorem | ecase2d 751 | Deduction for elimination by cases. |
| Theorem | ecase3 752 | Inference for elimination by cases. |
| Theorem | ecase 753 | Inference for elimination by cases. |
| Theorem | ecase3d 754 | Deduction for elimination by cases. |
| Theorem | ccase 755 | Inference for combining cases. |
| Theorem | ccased 756 | Deduction for combining cases. |
| Theorem | ccase2 757 | Inference for combining cases. |
| Theorem | 4cases 758 | Inference eliminating two antecedents from the four possible cases that result from their true/false combinations. |
| Theorem | niabn 759 | Miscellaneous inference relating falsehoods. |
| Theorem | dedlem0a 760 | Lemma for an alternate version of weak deduction theorem. |
| Theorem | dedlem0b 761 | Lemma for an alternate version of weak deduction theorem. |
| Theorem | dedlema 762 | Lemma for weak deduction theorem. |
| Theorem | dedlemb 763 | Lemma for weak deduction theorem. |