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Theorem ex-natded5.13 26426
Description: Theorem 5.13 of [Clemente] p. 20, translated line by line using the interpretation of natural deduction in Metamath. For information about ND and Metamath, see the page on Deduction Form and Natural Deduction in Metamath Proof Explorer. A much more efficient proof, using more of Metamath and MPE's capabilities, is shown in ex-natded5.13-2 26427. The original proof, which uses Fitch style, was written as follows (the leading "..." shows an embedded ND hypothesis, beginning with the initial assumption of the ND hypothesis):
#MPE#ND Expression MPE TranslationND Rationale MPE Rationale
115 (𝜓𝜒) (𝜑 → (𝜓𝜒)) Given \$e.
2;32 (𝜓𝜃) (𝜑 → (𝜓𝜃)) Given \$e. adantr 479 to move it into the ND hypothesis
39 𝜏 → ¬ 𝜒) (𝜑 → (¬ 𝜏 → ¬ 𝜒)) Given \$e. ad2antrr 757 to move it into the ND sub-hypothesis
41 ...| 𝜓 ((𝜑𝜓) → 𝜓) ND hypothesis assumption simpr 475
54 ... 𝜃 ((𝜑𝜓) → 𝜃) E 2,4 mpd 15 1,3
65 ... (𝜃𝜏) ((𝜑𝜓) → (𝜃𝜏)) I 5 orcd 405 4
76 ...| 𝜒 ((𝜑𝜒) → 𝜒) ND hypothesis assumption simpr 475
88 ... ...| ¬ 𝜏 (((𝜑𝜒) ∧ ¬ 𝜏) → ¬ 𝜏) (sub) ND hypothesis assumption simpr 475
911 ... ... ¬ 𝜒 (((𝜑𝜒) ∧ ¬ 𝜏) → ¬ 𝜒) E 3,8 mpd 15 8,10
107 ... ... 𝜒 (((𝜑𝜒) ∧ ¬ 𝜏) → 𝜒) IT 7 adantr 479 6
1112 ... ¬ ¬ 𝜏 ((𝜑𝜒) → ¬ ¬ 𝜏) ¬I 8,9,10 pm2.65da 597 7,11
1213 ... 𝜏 ((𝜑𝜒) → 𝜏) ¬E 11 notnotrd 126 12
1314 ... (𝜃𝜏) ((𝜑𝜒) → (𝜃𝜏)) I 12 olcd 406 13
1416 (𝜃𝜏) (𝜑 → (𝜃𝜏)) E 1,6,13 mpjaodan 822 5,14,15

The original used Latin letters; we have replaced them with Greek letters to follow Metamath naming conventions and so that it is easier to follow the Metamath translation. The Metamath line-for-line translation of this natural deduction approach precedes every line with an antecedent including 𝜑 and uses the Metamath equivalents of the natural deduction rules. To add an assumption, the antecedent is modified to include it (typically by using adantr 479; simpr 475 is useful when you want to depend directly on the new assumption). (Contributed by Mario Carneiro, 9-Feb-2017.) (Proof modification is discouraged.) (New usage is discouraged.)

Hypotheses
Ref Expression
ex-natded5.13.1 (𝜑 → (𝜓𝜒))
ex-natded5.13.2 (𝜑 → (𝜓𝜃))
ex-natded5.13.3 (𝜑 → (¬ 𝜏 → ¬ 𝜒))
Assertion
Ref Expression
ex-natded5.13 (𝜑 → (𝜃𝜏))

Proof of Theorem ex-natded5.13
StepHypRef Expression
1 simpr 475 . . . 4 ((𝜑𝜓) → 𝜓)
2 ex-natded5.13.2 . . . . 5 (𝜑 → (𝜓𝜃))
32adantr 479 . . . 4 ((𝜑𝜓) → (𝜓𝜃))
41, 3mpd 15 . . 3 ((𝜑𝜓) → 𝜃)
54orcd 405 . 2 ((𝜑𝜓) → (𝜃𝜏))
6 simpr 475 . . . . . 6 ((𝜑𝜒) → 𝜒)
76adantr 479 . . . . 5 (((𝜑𝜒) ∧ ¬ 𝜏) → 𝜒)
8 simpr 475 . . . . . 6 (((𝜑𝜒) ∧ ¬ 𝜏) → ¬ 𝜏)
9 ex-natded5.13.3 . . . . . . 7 (𝜑 → (¬ 𝜏 → ¬ 𝜒))
109ad2antrr 757 . . . . . 6 (((𝜑𝜒) ∧ ¬ 𝜏) → (¬ 𝜏 → ¬ 𝜒))
118, 10mpd 15 . . . . 5 (((𝜑𝜒) ∧ ¬ 𝜏) → ¬ 𝜒)
127, 11pm2.65da 597 . . . 4 ((𝜑𝜒) → ¬ ¬ 𝜏)
1312notnotrd 126 . . 3 ((𝜑𝜒) → 𝜏)
1413olcd 406 . 2 ((𝜑𝜒) → (𝜃𝜏))
15 ex-natded5.13.1 . 2 (𝜑 → (𝜓𝜒))
165, 14, 15mpjaodan 822 1 (𝜑 → (𝜃𝜏))
 Colors of variables: wff setvar class Syntax hints:  ¬ wn 3   → wi 4   ∨ wo 381   ∧ wa 382 This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8 This theorem depends on definitions:  df-bi 195  df-or 383  df-an 384 This theorem is referenced by: (None)
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