Theorem ss2in 4198

Description: Intersection of subclasses. (Contributed by NM, 5-May-2000.)

Assertion

Ref	Expression
ss2in	⊢ ((𝐴 ⊆ 𝐵 ∧ 𝐶 ⊆ 𝐷) → (𝐴 ∩ 𝐶) ⊆ (𝐵 ∩ 𝐷))

Proof of Theorem ss2in

Step	Hyp	Ref	Expression
1		ssrin 4195	. 2 ⊢ (𝐴 ⊆ 𝐵 → (𝐴 ∩ 𝐶) ⊆ (𝐵 ∩ 𝐶))
2		sslin 4196	. 2 ⊢ (𝐶 ⊆ 𝐷 → (𝐵 ∩ 𝐶) ⊆ (𝐵 ∩ 𝐷))
3	1, 2	sylan9ss 3951	1 ⊢ ((𝐴 ⊆ 𝐵 ∧ 𝐶 ⊆ 𝐷) → (𝐴 ∩ 𝐶) ⊆ (𝐵 ∩ 𝐷))

Syntax hints:   → wi 4   ∧ wa 395   ∩ cin 3904   ⊆ wss 3905

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1795  ax-4 1809  ax-5 1910  ax-6 1967  ax-7 2008  ax-8 2111  ax-9 2119  ax-ext 2701

This theorem depends on definitions:  df-bi 207  df-an 396  df-tru 1543  df-ex 1780  df-sb 2066  df-clab 2708  df-cleq 2721  df-clel 2803  df-rab 3397  df-v 3440  df-in 3912  df-ss 3922

This theorem is referenced by:  disjxiun  5092  f1un  6788  strleun  17086  dprdss  19928  dprd2da  19941  ablfac1b  19969  tgcl  22872  innei  23028  hausnei2  23256  bwth  23313  fbssfi  23740  fbunfip  23772  fgcl  23781  blin2  24333  vtxdun  29445  vtxdginducedm1  29507  5oai  31623  mayetes3i  31691  mdsl0  32272  neibastop1  36335  ismblfin  37643  heibor1lem  37791  pl42lem2N  39962  pl42lem3N  39963  ntrk2imkb  44013  ssin0  45036  iscnrm3llem2  48938