Theorem ssinss1OLD 4202

Description: Obsolete version of ssinss1 4201 as of 10-Jun-2026. (Contributed by NM, 14-Sep-1999.) (Proof modification is discouraged.) (New usage is discouraged.)

Assertion

Ref	Expression
ssinss1OLD	⊢ (𝐴 ⊆ 𝐶 → (𝐴 ∩ 𝐵) ⊆ 𝐶)

Proof of Theorem ssinss1OLD

Step	Hyp	Ref	Expression
1		inss1 4192	. 2 ⊢ (𝐴 ∩ 𝐵) ⊆ 𝐴
2		sstr2 3947	. 2 ⊢ ((𝐴 ∩ 𝐵) ⊆ 𝐴 → (𝐴 ⊆ 𝐶 → (𝐴 ∩ 𝐵) ⊆ 𝐶))
3	1, 2	ax-mp 5	1 ⊢ (𝐴 ⊆ 𝐶 → (𝐴 ∩ 𝐵) ⊆ 𝐶)

This proof depends on syntax axioms:   → wi 4   ∩ cin 3907   ⊆ wss 3908

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  ax-9 2156  ax-ext 2738

This proof depends on definitions:  df-bi 210  df-an 402  df-tru 1573  df-ex 1813  df-sb 2100  df-clab 2745  df-cleq 2758  df-clel 2841  df-v 3460  df-in 3915  df-ss 3925

This theorem is used by: (None)