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Theorem pm13.194 45150
Description: Theorem *13.194 in [WhiteheadRussell] p. 179. (Contributed by Andrew Salmon, 3-Jun-2011.)
Assertion
Ref Expression
pm13.194 ((𝜑𝑥 = 𝑦) ↔ ([𝑦 / 𝑥]𝜑𝜑𝑥 = 𝑦))

Proof of Theorem pm13.194
StepHypRef Expression
1 pm13.13a 45145 . . . 4 ((𝜑𝑥 = 𝑦) → [𝑦 / 𝑥]𝜑)
2 sbsbc 3748 . . . 4 ([𝑦 / 𝑥]𝜑[𝑦 / 𝑥]𝜑)
31, 2sylibr 237 . . 3 ((𝜑𝑥 = 𝑦) → [𝑦 / 𝑥]𝜑)
4 simpl 487 . . 3 ((𝜑𝑥 = 𝑦) → 𝜑)
5 simpr 489 . . 3 ((𝜑𝑥 = 𝑦) → 𝑥 = 𝑦)
63, 4, 53jca 1146 . 2 ((𝜑𝑥 = 𝑦) → ([𝑦 / 𝑥]𝜑𝜑𝑥 = 𝑦))
7 3simpc 1168 . 2 (([𝑦 / 𝑥]𝜑𝜑𝑥 = 𝑦) → (𝜑𝑥 = 𝑦))
86, 7impbii 212 1 ((𝜑𝑥 = 𝑦) ↔ ([𝑦 / 𝑥]𝜑𝜑𝑥 = 𝑦))
Colors of variables:    wff setvar class
This proof depends on syntax axioms:  wb 209  wa 400  w3a 1103  [wsb 2096  [wsbc 3744
This proof depends on axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1825  ax-4 1839  ax-5 1940  ax-6 1997  ax-7 2038  ax-8 2145  ax-9 2153  ax-12 2213  ax-ext 2735
This proof depends on definitions:  df-bi 210  df-an 401  df-3an 1105  df-ex 1810  df-sb 2097  df-clab 2742  df-cleq 2755  df-clel 2838  df-sbc 3745
This theorem is used by: (None)
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