Theorem ssneld 3934

Description: If a class is not in another class, it is also not in a subclass of that class. Deduction form. (Contributed by David Moews, 1-May-2017.)

Hypothesis

Ref	Expression
ssneld.1	⊢ (𝜑 → 𝐴 ⊆ 𝐵)

Assertion

Ref	Expression
ssneld	⊢ (𝜑 → (¬ 𝐶 ∈ 𝐵 → ¬ 𝐶 ∈ 𝐴))

Proof of Theorem ssneld

Step	Hyp	Ref	Expression
1		ssneld.1	. . 3 ⊢ (𝜑 → 𝐴 ⊆ 𝐵)
2	1	sseld 3931	. 2 ⊢ (𝜑 → (𝐶 ∈ 𝐴 → 𝐶 ∈ 𝐵))
3	2	con3d 152	1 ⊢ (𝜑 → (¬ 𝐶 ∈ 𝐵 → ¬ 𝐶 ∈ 𝐴))

Syntax hints:  ¬ wn 3   → wi 4   ∈ wcel 2110   ⊆ wss 3900

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1796  ax-4 1810  ax-5 1911  ax-6 1968  ax-7 2009  ax-8 2112

This theorem depends on definitions:  df-bi 207  df-an 396  df-ex 1781  df-clel 2804  df-ss 3917

This theorem is referenced by:  ssneldd  3935  kmlem2  10035  hashbclem  14351  prodss  15846  coprmproddvdslem  16565  mrissmrid  17539  mpfrcl  22013  onsuct0  36454  ftc1anc  37720  dvhdimlem  41462  dvh3dim2  41466  dvh3dim3N  41467  mapdh9a  41807  hdmapval0  41851  hdmap11lem2  41860  iundjiunlem  46476  elbigolo1  48568