P. 8 of Theorem List - Intuitionistic Logic Explorer

Theorem List for Intuitionistic Logic Explorer - 701-800   *Has distinct variable group(s)

Type	Label	Description
Statement
Theorem	pm5.19 701	Theorem *5.19 of [WhiteheadRussell] p. 124. (Contributed by NM, 3-Jan-2005.) (Revised by Mario Carneiro, 31-Jan-2015.)
|- -. ( ph <-> -. ph )
Theorem	pm4.8 702	Theorem *4.8 of [WhiteheadRussell] p. 122. This one holds for all propositions, but compare with pm4.81dc 903 which requires a decidability condition. (Contributed by NM, 3-Jan-2005.)
|- ( ( ph -> -. ph ) <-> -. ph )
1.2.6  Logical disjunction
Syntax	wo 703	Extend wff definition to include disjunction ('or').
wff ( ph \/ ps )
Axiom	ax-io 704	Definition of 'or'. One of the axioms of propositional logic. (Contributed by Mario Carneiro, 31-Jan-2015.) Use its alias jaob 705 instead. (New usage is discouraged.)
|- ( ( ( ph \/ ch ) -> ps ) <-> ( ( ph -> ps ) /\ ( ch -> ps ) ) )
Theorem	jaob 705	Disjunction of antecedents. Compare Theorem *4.77 of [WhiteheadRussell] p. 121. Alias of ax-io 704. (Contributed by NM, 30-May-1994.) (Revised by Mario Carneiro, 31-Jan-2015.)
|- ( ( ( ph \/ ch ) -> ps ) <-> ( ( ph -> ps ) /\ ( ch -> ps ) ) )
Theorem	olc 706	Introduction of a disjunct. Axiom *1.3 of [WhiteheadRussell] p. 96. (Contributed by NM, 30-Aug-1993.) (Revised by NM, 31-Jan-2015.)
|- ( ph -> ( ps \/ ph ) )
Theorem	orc 707	Introduction of a disjunct. Theorem *2.2 of [WhiteheadRussell] p. 104. (Contributed by NM, 30-Aug-1993.) (Revised by NM, 31-Jan-2015.)
|- ( ph -> ( ph \/ ps ) )
Theorem	pm2.67-2 708	Slight generalization of Theorem *2.67 of [WhiteheadRussell] p. 107. (Contributed by NM, 3-Jan-2005.) (Revised by NM, 9-Dec-2012.)
|- ( ( ( ph \/ ch ) -> ps ) -> ( ph -> ps ) )
Theorem	oibabs 709	Absorption of disjunction into equivalence. (Contributed by NM, 6-Aug-1995.) (Proof shortened by Wolf Lammen, 3-Nov-2013.)
|- ( ( ( ph \/ ps ) -> ( ph <-> ps ) ) <-> ( ph <-> ps ) )
Theorem	pm3.44 710	Theorem *3.44 of [WhiteheadRussell] p. 113. (Contributed by NM, 3-Jan-2005.) (Proof shortened by Wolf Lammen, 3-Oct-2013.)
|- ( ( ( ps -> ph ) /\ ( ch -> ph ) ) -> ( ( ps \/ ch ) -> ph ) )
Theorem	jaoi 711	Inference disjoining the antecedents of two implications. (Contributed by NM, 5-Apr-1994.) (Revised by NM, 31-Jan-2015.)
|- ( ph -> ps )   &    |- ( ch -> ps )   =>    |- ( ( ph \/ ch ) -> ps )
Theorem	jaod 712	Deduction disjoining the antecedents of two implications. (Contributed by NM, 18-Aug-1994.) (Revised by NM, 4-Apr-2013.)
|- ( ph -> ( ps -> ch ) )   &    |- ( ph -> ( th -> ch ) )   =>    |- ( ph -> ( ( ps \/ th ) -> ch ) )
Theorem	mpjaod 713	Eliminate a disjunction in a deduction. (Contributed by Mario Carneiro, 29-May-2016.)
|- ( ph -> ( ps -> ch ) )   &    |- ( ph -> ( th -> ch ) )   &    |- ( ph -> ( ps \/ th ) )   =>    |- ( ph -> ch )
Theorem	jaao 714	Inference conjoining and disjoining the antecedents of two implications. (Contributed by NM, 30-Sep-1999.)
|- ( ph -> ( ps -> ch ) )   &    |- ( th -> ( ta -> ch ) )   =>    |- ( ( ph /\ th ) -> ( ( ps \/ ta ) -> ch ) )
Theorem	jaoa 715	Inference disjoining and conjoining the antecedents of two implications. (Contributed by Stefan Allan, 1-Nov-2008.)
|- ( ph -> ( ps -> ch ) )   &    |- ( th -> ( ta -> ch ) )   =>    |- ( ( ph \/ th ) -> ( ( ps /\ ta ) -> ch ) )
Theorem	imorr 716	Implication in terms of disjunction. One direction of theorem *4.6 of [WhiteheadRussell] p. 120. The converse holds for decidable propositions, as seen at imordc 892. (Contributed by Jim Kingdon, 21-Jul-2018.)
|- ( ( -. ph \/ ps ) -> ( ph -> ps ) )
Theorem	pm2.53 717	Theorem *2.53 of [WhiteheadRussell] p. 107. This holds intuitionistically, although its converse does not (see pm2.54dc 886). (Contributed by NM, 3-Jan-2005.) (Revised by NM, 31-Jan-2015.)
|- ( ( ph \/ ps ) -> ( -. ph -> ps ) )
Theorem	ori 718	Infer implication from disjunction. (Contributed by NM, 11-Jun-1994.) (Revised by Mario Carneiro, 31-Jan-2015.)
|- ( ph \/ ps )   =>    |- ( -. ph -> ps )
Theorem	ord 719	Deduce implication from disjunction. (Contributed by NM, 18-May-1994.) (Revised by Mario Carneiro, 31-Jan-2015.)
|- ( ph -> ( ps \/ ch ) )   =>    |- ( ph -> ( -. ps -> ch ) )
Theorem	orel1 720	Elimination of disjunction by denial of a disjunct. Theorem *2.55 of [WhiteheadRussell] p. 107. (Contributed by NM, 12-Aug-1994.) (Proof shortened by Wolf Lammen, 21-Jul-2012.)
|- ( -. ph -> ( ( ph \/ ps ) -> ps ) )
Theorem	orel2 721	Elimination of disjunction by denial of a disjunct. Theorem *2.56 of [WhiteheadRussell] p. 107. (Contributed by NM, 12-Aug-1994.) (Proof shortened by Wolf Lammen, 5-Apr-2013.)
|- ( -. ph -> ( ( ps \/ ph ) -> ps ) )
Theorem	pm1.4 722	Axiom *1.4 of [WhiteheadRussell] p. 96. (Contributed by NM, 3-Jan-2005.) (Revised by NM, 15-Nov-2012.)
|- ( ( ph \/ ps ) -> ( ps \/ ph ) )
Theorem	orcom 723	Commutative law for disjunction. Theorem *4.31 of [WhiteheadRussell] p. 118. (Contributed by NM, 5-Aug-1993.) (Proof shortened by Wolf Lammen, 15-Nov-2012.)
|- ( ( ph \/ ps ) <-> ( ps \/ ph ) )
Theorem	orcomd 724	Commutation of disjuncts in consequent. (Contributed by NM, 2-Dec-2010.)
|- ( ph -> ( ps \/ ch ) )   =>    |- ( ph -> ( ch \/ ps ) )
Theorem	orcoms 725	Commutation of disjuncts in antecedent. (Contributed by NM, 2-Dec-2012.)
|- ( ( ph \/ ps ) -> ch )   =>    |- ( ( ps \/ ph ) -> ch )
Theorem	orci 726	Deduction introducing a disjunct. (Contributed by NM, 19-Jan-2008.) (Revised by Mario Carneiro, 31-Jan-2015.)
|- ph   =>    |- ( ph \/ ps )
Theorem	olci 727	Deduction introducing a disjunct. (Contributed by NM, 19-Jan-2008.) (Revised by Mario Carneiro, 31-Jan-2015.)
|- ph   =>    |- ( ps \/ ph )
Theorem	orcd 728	Deduction introducing a disjunct. (Contributed by NM, 20-Sep-2007.)
|- ( ph -> ps )   =>    |- ( ph -> ( ps \/ ch ) )
Theorem	olcd 729	Deduction introducing a disjunct. (Contributed by NM, 11-Apr-2008.) (Proof shortened by Wolf Lammen, 3-Oct-2013.)
|- ( ph -> ps )   =>    |- ( ph -> ( ch \/ ps ) )
Theorem	orcs 730	Deduction eliminating disjunct. Notational convention: We sometimes suffix with "s" the label of an inference that manipulates an antecedent, leaving the consequent unchanged. The "s" means that the inference eliminates the need for a syllogism (syl 14) -type inference in a proof. (Contributed by NM, 21-Jun-1994.)
|- ( ( ph \/ ps ) -> ch )   =>    |- ( ph -> ch )
Theorem	olcs 731	Deduction eliminating disjunct. (Contributed by NM, 21-Jun-1994.) (Proof shortened by Wolf Lammen, 3-Oct-2013.)
|- ( ( ph \/ ps ) -> ch )   =>    |- ( ps -> ch )
Theorem	pm2.07 732	Theorem *2.07 of [WhiteheadRussell] p. 101. (Contributed by NM, 3-Jan-2005.)
|- ( ph -> ( ph \/ ph ) )
Theorem	pm2.45 733	Theorem *2.45 of [WhiteheadRussell] p. 106. (Contributed by NM, 3-Jan-2005.)
|- ( -. ( ph \/ ps ) -> -. ph )
Theorem	pm2.46 734	Theorem *2.46 of [WhiteheadRussell] p. 106. (Contributed by NM, 3-Jan-2005.)
|- ( -. ( ph \/ ps ) -> -. ps )
Theorem	pm2.47 735	Theorem *2.47 of [WhiteheadRussell] p. 107. (Contributed by NM, 3-Jan-2005.)
|- ( -. ( ph \/ ps ) -> ( -. ph \/ ps ) )
Theorem	pm2.48 736	Theorem *2.48 of [WhiteheadRussell] p. 107. (Contributed by NM, 3-Jan-2005.)
|- ( -. ( ph \/ ps ) -> ( ph \/ -. ps ) )
Theorem	pm2.49 737	Theorem *2.49 of [WhiteheadRussell] p. 107. (Contributed by NM, 3-Jan-2005.)
|- ( -. ( ph \/ ps ) -> ( -. ph \/ -. ps ) )
Theorem	pm2.67 738	Theorem *2.67 of [WhiteheadRussell] p. 107. (Contributed by NM, 3-Jan-2005.) (Revised by NM, 9-Dec-2012.)
|- ( ( ( ph \/ ps ) -> ps ) -> ( ph -> ps ) )
Theorem	biorf 739	A wff is equivalent to its disjunction with falsehood. Theorem *4.74 of [WhiteheadRussell] p. 121. (Contributed by NM, 23-Mar-1995.) (Proof shortened by Wolf Lammen, 18-Nov-2012.)
|- ( -. ph -> ( ps <-> ( ph \/ ps ) ) )
Theorem	biortn 740	A wff is equivalent to its negated disjunction with falsehood. (Contributed by NM, 9-Jul-2012.)
|- ( ph -> ( ps <-> ( -. ph \/ ps ) ) )
Theorem	biorfi 741	A wff is equivalent to its disjunction with falsehood. (Contributed by NM, 23-Mar-1995.)
|- -. ph   =>    |- ( ps <-> ( ps \/ ph ) )
Theorem	pm2.621 742	Theorem *2.621 of [WhiteheadRussell] p. 107. (Contributed by NM, 3-Jan-2005.) (Revised by NM, 13-Dec-2013.)
|- ( ( ph -> ps ) -> ( ( ph \/ ps ) -> ps ) )
Theorem	pm2.62 743	Theorem *2.62 of [WhiteheadRussell] p. 107. (Contributed by NM, 3-Jan-2005.) (Proof shortened by Wolf Lammen, 13-Dec-2013.)
|- ( ( ph \/ ps ) -> ( ( ph -> ps ) -> ps ) )
Theorem	imorri 744	Infer implication from disjunction. (Contributed by Jonathan Ben-Naim, 3-Jun-2011.) (Revised by Mario Carneiro, 31-Jan-2015.)
|- ( -. ph \/ ps )   =>    |- ( ph -> ps )
Theorem	pm4.52im 745	One direction of theorem *4.52 of [WhiteheadRussell] p. 120. The converse also holds in classical logic. (Contributed by Jim Kingdon, 27-Jul-2018.)
|- ( ( ph /\ -. ps ) -> -. ( -. ph \/ ps ) )
Theorem	pm4.53r 746	One direction of theorem *4.53 of [WhiteheadRussell] p. 120. The converse also holds in classical logic. (Contributed by Jim Kingdon, 27-Jul-2018.)
|- ( ( -. ph \/ ps ) -> -. ( ph /\ -. ps ) )
Theorem	ioran 747	Negated disjunction in terms of conjunction. This version of DeMorgan's law is a biconditional for all propositions (not just decidable ones), unlike oranim 776, anordc 951, or ianordc 894. Compare Theorem *4.56 of [WhiteheadRussell] p. 120. (Contributed by NM, 5-Aug-1993.) (Revised by Mario Carneiro, 31-Jan-2015.)
|- ( -. ( ph \/ ps ) <-> ( -. ph /\ -. ps ) )
Theorem	pm3.14 748	Theorem *3.14 of [WhiteheadRussell] p. 111. One direction of De Morgan's law). The biconditional holds for decidable propositions as seen at ianordc 894. The converse holds for decidable propositions, as seen at pm3.13dc 954. (Contributed by NM, 3-Jan-2005.) (Revised by Mario Carneiro, 31-Jan-2015.)
|- ( ( -. ph \/ -. ps ) -> -. ( ph /\ ps ) )
Theorem	pm3.1 749	Theorem *3.1 of [WhiteheadRussell] p. 111. The converse holds for decidable propositions, as seen at anordc 951. (Contributed by NM, 3-Jan-2005.) (Revised by Mario Carneiro, 31-Jan-2015.)
|- ( ( ph /\ ps ) -> -. ( -. ph \/ -. ps ) )
Theorem	jao 750	Disjunction of antecedents. Compare Theorem *3.44 of [WhiteheadRussell] p. 113. (Contributed by NM, 5-Apr-1994.) (Proof shortened by Wolf Lammen, 4-Apr-2013.)
|- ( ( ph -> ps ) -> ( ( ch -> ps ) -> ( ( ph \/ ch ) -> ps ) ) )
Theorem	pm1.2 751	Axiom *1.2 (Taut) of [WhiteheadRussell] p. 96. (Contributed by NM, 3-Jan-2005.) (Revised by NM, 10-Mar-2013.)
|- ( ( ph \/ ph ) -> ph )
Theorem	oridm 752	Idempotent law for disjunction. Theorem *4.25 of [WhiteheadRussell] p. 117. (Contributed by NM, 5-Aug-1993.) (Proof shortened by Andrew Salmon, 16-Apr-2011.) (Proof shortened by Wolf Lammen, 10-Mar-2013.)
|- ( ( ph \/ ph ) <-> ph )
Theorem	pm4.25 753	Theorem *4.25 of [WhiteheadRussell] p. 117. (Contributed by NM, 3-Jan-2005.)
|- ( ph <-> ( ph \/ ph ) )
Theorem	orim12i 754	Disjoin antecedents and consequents of two premises. (Contributed by NM, 6-Jun-1994.) (Proof shortened by Wolf Lammen, 25-Jul-2012.)
|- ( ph -> ps )   &    |- ( ch -> th )   =>    |- ( ( ph \/ ch ) -> ( ps \/ th ) )
Theorem	orim1i 755	Introduce disjunct to both sides of an implication. (Contributed by NM, 6-Jun-1994.)
|- ( ph -> ps )   =>    |- ( ( ph \/ ch ) -> ( ps \/ ch ) )
Theorem	orim2i 756	Introduce disjunct to both sides of an implication. (Contributed by NM, 6-Jun-1994.)
|- ( ph -> ps )   =>    |- ( ( ch \/ ph ) -> ( ch \/ ps ) )
Theorem	orbi2i 757	Inference adding a left disjunct to both sides of a logical equivalence. (Contributed by NM, 5-Aug-1993.) (Proof shortened by Wolf Lammen, 12-Dec-2012.)
|- ( ph <-> ps )   =>    |- ( ( ch \/ ph ) <-> ( ch \/ ps ) )
Theorem	orbi1i 758	Inference adding a right disjunct to both sides of a logical equivalence. (Contributed by NM, 5-Aug-1993.)
|- ( ph <-> ps )   =>    |- ( ( ph \/ ch ) <-> ( ps \/ ch ) )
Theorem	orbi12i 759	Infer the disjunction of two equivalences. (Contributed by NM, 5-Aug-1993.)
|- ( ph <-> ps )   &    |- ( ch <-> th )   =>    |- ( ( ph \/ ch ) <-> ( ps \/ th ) )
Theorem	pm1.5 760	Axiom *1.5 (Assoc) of [WhiteheadRussell] p. 96. (Contributed by NM, 3-Jan-2005.)
|- ( ( ph \/ ( ps \/ ch ) ) -> ( ps \/ ( ph \/ ch ) ) )
Theorem	or12 761	Swap two disjuncts. (Contributed by NM, 5-Aug-1993.) (Proof shortened by Wolf Lammen, 14-Nov-2012.)
|- ( ( ph \/ ( ps \/ ch ) ) <-> ( ps \/ ( ph \/ ch ) ) )
Theorem	orass 762	Associative law for disjunction. Theorem *4.33 of [WhiteheadRussell] p. 118. (Contributed by NM, 5-Aug-1993.) (Proof shortened by Andrew Salmon, 26-Jun-2011.)
|- ( ( ( ph \/ ps ) \/ ch ) <-> ( ph \/ ( ps \/ ch ) ) )
Theorem	pm2.31 763	Theorem *2.31 of [WhiteheadRussell] p. 104. (Contributed by NM, 3-Jan-2005.)
|- ( ( ph \/ ( ps \/ ch ) ) -> ( ( ph \/ ps ) \/ ch ) )
Theorem	pm2.32 764	Theorem *2.32 of [WhiteheadRussell] p. 105. (Contributed by NM, 3-Jan-2005.)
|- ( ( ( ph \/ ps ) \/ ch ) -> ( ph \/ ( ps \/ ch ) ) )
Theorem	or32 765	A rearrangement of disjuncts. (Contributed by NM, 18-Oct-1995.) (Proof shortened by Andrew Salmon, 26-Jun-2011.)
|- ( ( ( ph \/ ps ) \/ ch ) <-> ( ( ph \/ ch ) \/ ps ) )
Theorem	or4 766	Rearrangement of 4 disjuncts. (Contributed by NM, 12-Aug-1994.)
|- ( ( ( ph \/ ps ) \/ ( ch \/ th ) ) <-> ( ( ph \/ ch ) \/ ( ps \/ th ) ) )
Theorem	or42 767	Rearrangement of 4 disjuncts. (Contributed by NM, 10-Jan-2005.)
|- ( ( ( ph \/ ps ) \/ ( ch \/ th ) ) <-> ( ( ph \/ ch ) \/ ( th \/ ps ) ) )
Theorem	orordi 768	Distribution of disjunction over disjunction. (Contributed by NM, 25-Feb-1995.)
|- ( ( ph \/ ( ps \/ ch ) ) <-> ( ( ph \/ ps ) \/ ( ph \/ ch ) ) )
Theorem	orordir 769	Distribution of disjunction over disjunction. (Contributed by NM, 25-Feb-1995.)
|- ( ( ( ph \/ ps ) \/ ch ) <-> ( ( ph \/ ch ) \/ ( ps \/ ch ) ) )
Theorem	pm2.3 770	Theorem *2.3 of [WhiteheadRussell] p. 104. (Contributed by NM, 3-Jan-2005.)
|- ( ( ph \/ ( ps \/ ch ) ) -> ( ph \/ ( ch \/ ps ) ) )
Theorem	pm2.41 771	Theorem *2.41 of [WhiteheadRussell] p. 106. (Contributed by NM, 3-Jan-2005.)
|- ( ( ps \/ ( ph \/ ps ) ) -> ( ph \/ ps ) )
Theorem	pm2.42 772	Theorem *2.42 of [WhiteheadRussell] p. 106. (Contributed by NM, 3-Jan-2005.)
|- ( ( -. ph \/ ( ph -> ps ) ) -> ( ph -> ps ) )
Theorem	pm2.4 773	Theorem *2.4 of [WhiteheadRussell] p. 106. (Contributed by NM, 3-Jan-2005.)
|- ( ( ph \/ ( ph \/ ps ) ) -> ( ph \/ ps ) )
Theorem	pm4.44 774	Theorem *4.44 of [WhiteheadRussell] p. 119. (Contributed by NM, 3-Jan-2005.)
|- ( ph <-> ( ph \/ ( ph /\ ps ) ) )
Theorem	pm4.56 775	Theorem *4.56 of [WhiteheadRussell] p. 120. (Contributed by NM, 3-Jan-2005.)
|- ( ( -. ph /\ -. ps ) <-> -. ( ph \/ ps ) )
Theorem	oranim 776	Disjunction in terms of conjunction (DeMorgan's law). One direction of Theorem *4.57 of [WhiteheadRussell] p. 120. The converse does not hold intuitionistically but does hold in classical logic. (Contributed by Jim Kingdon, 25-Jul-2018.)
|- ( ( ph \/ ps ) -> -. ( -. ph /\ -. ps ) )
Theorem	pm4.78i 777	Implication distributes over disjunction. One direction of Theorem *4.78 of [WhiteheadRussell] p. 121. The converse holds in classical logic. (Contributed by Jim Kingdon, 15-Jan-2018.)
|- ( ( ( ph -> ps ) \/ ( ph -> ch ) ) -> ( ph -> ( ps \/ ch ) ) )
Theorem	mtord 778	A modus tollens deduction involving disjunction. (Contributed by Jeff Hankins, 15-Jul-2009.) (Revised by Mario Carneiro, 31-Jan-2015.)
|- ( ph -> -. ch )   &    |- ( ph -> -. th )   &    |- ( ph -> ( ps -> ( ch \/ th ) ) )   =>    |- ( ph -> -. ps )
Theorem	pm4.45 779	Theorem *4.45 of [WhiteheadRussell] p. 119. (Contributed by NM, 3-Jan-2005.)
|- ( ph <-> ( ph /\ ( ph \/ ps ) ) )
Theorem	pm3.48 780	Theorem *3.48 of [WhiteheadRussell] p. 114. (Contributed by NM, 28-Jan-1997.) (Revised by NM, 1-Dec-2012.)
|- ( ( ( ph -> ps ) /\ ( ch -> th ) ) -> ( ( ph \/ ch ) -> ( ps \/ th ) ) )
Theorem	orim12d 781	Disjoin antecedents and consequents in a deduction. (Contributed by NM, 10-May-1994.)
|- ( ph -> ( ps -> ch ) )   &    |- ( ph -> ( th -> ta ) )   =>    |- ( ph -> ( ( ps \/ th ) -> ( ch \/ ta ) ) )
Theorem	orim1d 782	Disjoin antecedents and consequents in a deduction. (Contributed by NM, 23-Apr-1995.)
|- ( ph -> ( ps -> ch ) )   =>    |- ( ph -> ( ( ps \/ th ) -> ( ch \/ th ) ) )
Theorem	orim2d 783	Disjoin antecedents and consequents in a deduction. (Contributed by NM, 23-Apr-1995.)
|- ( ph -> ( ps -> ch ) )   =>    |- ( ph -> ( ( th \/ ps ) -> ( th \/ ch ) ) )
Theorem	orim2 784	Axiom *1.6 (Sum) of [WhiteheadRussell] p. 97. (Contributed by NM, 3-Jan-2005.)
|- ( ( ps -> ch ) -> ( ( ph \/ ps ) -> ( ph \/ ch ) ) )
Theorem	orbi2d 785	Deduction adding a left disjunct to both sides of a logical equivalence. (Contributed by NM, 5-Aug-1993.) (Revised by Mario Carneiro, 31-Jan-2015.)
|- ( ph -> ( ps <-> ch ) )   =>    |- ( ph -> ( ( th \/ ps ) <-> ( th \/ ch ) ) )
Theorem	orbi1d 786	Deduction adding a right disjunct to both sides of a logical equivalence. (Contributed by NM, 5-Aug-1993.)
|- ( ph -> ( ps <-> ch ) )   =>    |- ( ph -> ( ( ps \/ th ) <-> ( ch \/ th ) ) )
Theorem	orbi1 787	Theorem *4.37 of [WhiteheadRussell] p. 118. (Contributed by NM, 3-Jan-2005.)
|- ( ( ph <-> ps ) -> ( ( ph \/ ch ) <-> ( ps \/ ch ) ) )
Theorem	orbi12d 788	Deduction joining two equivalences to form equivalence of disjunctions. (Contributed by NM, 5-Aug-1993.)
|- ( ph -> ( ps <-> ch ) )   &    |- ( ph -> ( th <-> ta ) )   =>    |- ( ph -> ( ( ps \/ th ) <-> ( ch \/ ta ) ) )
Theorem	pm5.61 789	Theorem *5.61 of [WhiteheadRussell] p. 125. (Contributed by NM, 3-Jan-2005.) (Proof shortened by Wolf Lammen, 30-Jun-2013.)
|- ( ( ( ph \/ ps ) /\ -. ps ) <-> ( ph /\ -. ps ) )
Theorem	jaoian 790	Inference disjoining the antecedents of two implications. (Contributed by NM, 23-Oct-2005.)
|- ( ( ph /\ ps ) -> ch )   &    |- ( ( th /\ ps ) -> ch )   =>    |- ( ( ( ph \/ th ) /\ ps ) -> ch )
Theorem	jao1i 791	Add a disjunct in the antecedent of an implication. (Contributed by Rodolfo Medina, 24-Sep-2010.)
|- ( ps -> ( ch -> ph ) )   =>    |- ( ( ph \/ ps ) -> ( ch -> ph ) )
Theorem	jaodan 792	Deduction disjoining the antecedents of two implications. (Contributed by NM, 14-Oct-2005.)
|- ( ( ph /\ ps ) -> ch )   &    |- ( ( ph /\ th ) -> ch )   =>    |- ( ( ph /\ ( ps \/ th ) ) -> ch )
Theorem	mpjaodan 793	Eliminate a disjunction in a deduction. A translation of natural deduction rule \/ E ( \/ elimination). (Contributed by Mario Carneiro, 29-May-2016.)
|- ( ( ph /\ ps ) -> ch )   &    |- ( ( ph /\ th ) -> ch )   &    |- ( ph -> ( ps \/ th ) )   =>    |- ( ph -> ch )
Theorem	pm4.77 794	Theorem *4.77 of [WhiteheadRussell] p. 121. (Contributed by NM, 3-Jan-2005.)
|- ( ( ( ps -> ph ) /\ ( ch -> ph ) ) <-> ( ( ps \/ ch ) -> ph ) )
Theorem	pm2.63 795	Theorem *2.63 of [WhiteheadRussell] p. 107. (Contributed by NM, 3-Jan-2005.)
|- ( ( ph \/ ps ) -> ( ( -. ph \/ ps ) -> ps ) )
Theorem	pm2.64 796	Theorem *2.64 of [WhiteheadRussell] p. 107. (Contributed by NM, 3-Jan-2005.)
|- ( ( ph \/ ps ) -> ( ( ph \/ -. ps ) -> ph ) )
Theorem	pm5.53 797	Theorem *5.53 of [WhiteheadRussell] p. 125. (Contributed by NM, 3-Jan-2005.)
|- ( ( ( ( ph \/ ps ) \/ ch ) -> th ) <-> ( ( ( ph -> th ) /\ ( ps -> th ) ) /\ ( ch -> th ) ) )
Theorem	pm2.38 798	Theorem *2.38 of [WhiteheadRussell] p. 105. (Contributed by NM, 6-Mar-2008.)
|- ( ( ps -> ch ) -> ( ( ps \/ ph ) -> ( ch \/ ph ) ) )
Theorem	pm2.36 799	Theorem *2.36 of [WhiteheadRussell] p. 105. (Contributed by NM, 6-Mar-2008.)
|- ( ( ps -> ch ) -> ( ( ph \/ ps ) -> ( ch \/ ph ) ) )
Theorem	pm2.37 800	Theorem *2.37 of [WhiteheadRussell] p. 105. (Contributed by NM, 6-Mar-2008.)
|- ( ( ps -> ch ) -> ( ( ps \/ ph ) -> ( ph \/ ch ) ) )