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Mirrors > Home > MPE Home > Th. List > Mathboxes > bj-currypeirce | Structured version Visualization version GIF version |
Description: Curry's axiom (a non-intuitionistic statement sometimes called a paradox of material implication) implies Peirce's axiom peirce 193 over minimal implicational calculus and the axiomatic definition of disjunction (olc 399, orc 400, jao 534). A shorter proof from bj-orim2 32541, pm1.2 535, syl6com 37 is possible if we accept to use pm1.2 535, itself a direct consequence of jao 534. (Contributed by BJ, 15-Jun-2021.) (Proof modification is discouraged.) (New usage is discouraged.) |
Ref | Expression |
---|---|
bj-currypeirce | ⊢ ((𝜑 ∨ (𝜑 → 𝜓)) → (((𝜑 → 𝜓) → 𝜑) → 𝜑)) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | olc 399 | . . 3 ⊢ (𝜑 → (𝜑 ∨ 𝜑)) | |
2 | 1 | imim2i 16 | . . 3 ⊢ (((𝜑 → 𝜓) → 𝜑) → ((𝜑 → 𝜓) → (𝜑 ∨ 𝜑))) |
3 | jao 534 | . . 3 ⊢ ((𝜑 → (𝜑 ∨ 𝜑)) → (((𝜑 → 𝜓) → (𝜑 ∨ 𝜑)) → ((𝜑 ∨ (𝜑 → 𝜓)) → (𝜑 ∨ 𝜑)))) | |
4 | 1, 2, 3 | mpsyl 68 | . 2 ⊢ (((𝜑 → 𝜓) → 𝜑) → ((𝜑 ∨ (𝜑 → 𝜓)) → (𝜑 ∨ 𝜑))) |
5 | id 22 | . . 3 ⊢ (𝜑 → 𝜑) | |
6 | jao 534 | . . 3 ⊢ ((𝜑 → 𝜑) → ((𝜑 → 𝜑) → ((𝜑 ∨ 𝜑) → 𝜑))) | |
7 | 5, 5, 6 | mp2 9 | . 2 ⊢ ((𝜑 ∨ 𝜑) → 𝜑) |
8 | 4, 7 | syl6com 37 | 1 ⊢ ((𝜑 ∨ (𝜑 → 𝜓)) → (((𝜑 → 𝜓) → 𝜑) → 𝜑)) |
Colors of variables: wff setvar class |
Syntax hints: → wi 4 ∨ wo 383 |
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 197 df-or 385 df-an 386 |
This theorem is referenced by: (None) |
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