Theorem ssneld 3940

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 3937	. 2 ⊢ (𝜑 → (𝐶 ∈ 𝐴 → 𝐶 ∈ 𝐵))
3	2	con3d 153	1 ⊢ (𝜑 → (¬ 𝐶 ∈ 𝐵 → ¬ 𝐶 ∈ 𝐴))

This proof depends on syntax axioms:  ¬ wn 3   → wi 4   ∈ wcel 2146   ⊆ wss 3906

This proof depends on axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1828  ax-4 1842  ax-5 1943  ax-6 2000  ax-7 2041  ax-8 2148

This proof depends on definitions:  df-bi 210  df-an 402  df-ex 1813  df-clel 2840  df-ss 3923

This theorem is used by:  ssneldd  3941  kmlem2  10147  hashbclem  14502  prodss  16019  coprmproddvdslem  16737  mrissmrid  17714  mpfrcl  22265  onsuct0  36985  ftc1anc  38385  dvhdimlem  42251  dvh3dim2  42255  dvh3dim3N  42256  mapdh9a  42596  hdmapval0  42640  hdmap11lem2  42649  iundjiunlem  47206  elbigolo1  49370