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Theorem ssnelpssd 3290
 Description: Subclass inclusion with one element of the superclass missing is proper subclass inclusion. Deduction form of ssnelpss 3289. (Contributed by David Moews, 1-May-2017.)
Hypotheses
Ref Expression
ssnelpssd.1 (𝜑𝐴𝐵)
ssnelpssd.2 (𝜑𝐶𝐵)
ssnelpssd.3 (𝜑 → ¬ 𝐶𝐴)
Assertion
Ref Expression
ssnelpssd (𝜑𝐴𝐵)

Proof of Theorem ssnelpssd
StepHypRef Expression
1 ssnelpssd.2 . 2 (𝜑𝐶𝐵)
2 ssnelpssd.3 . 2 (𝜑 → ¬ 𝐶𝐴)
3 ssnelpssd.1 . . 3 (𝜑𝐴𝐵)
4 ssnelpss 3289 . . 3 (𝐴𝐵 → ((𝐶𝐵 ∧ ¬ 𝐶𝐴) → 𝐴𝐵))
53, 4syl 14 . 2 (𝜑 → ((𝐶𝐵 ∧ ¬ 𝐶𝐴) → 𝐴𝐵))
61, 2, 5mp2and 409 1 (𝜑𝐴𝐵)
 Colors of variables: wff set class Syntax hints:  ¬ wn 3   → wi 4   ∧ wa 97   ∈ wcel 1393   ⊆ wss 2917   ⊊ wpss 2918 This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-mp 7  ax-ia1 99  ax-ia2 100  ax-ia3 101  ax-in1 544  ax-in2 545  ax-5 1336  ax-gen 1338  ax-ie1 1382  ax-ie2 1383  ax-4 1400  ax-17 1419  ax-ial 1427  ax-ext 2022 This theorem depends on definitions:  df-bi 110  df-cleq 2033  df-clel 2036  df-ne 2206  df-pss 2933 This theorem is referenced by: (None)
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