Theorem ssind 3300

Description: A deduction showing that a subclass of two classes is a subclass of their intersection. (Contributed by Jonathan Ben-Naim, 3-Jun-2011.)

Hypotheses

Ref	Expression
ssind.1	⊢ (𝜑 → 𝐴 ⊆ 𝐵)
ssind.2	⊢ (𝜑 → 𝐴 ⊆ 𝐶)

Assertion

Ref	Expression
ssind	⊢ (𝜑 → 𝐴 ⊆ (𝐵 ∩ 𝐶))

Proof of Theorem ssind

Step	Hyp	Ref	Expression
1		ssind.1	. 2 ⊢ (𝜑 → 𝐴 ⊆ 𝐵)
2		ssind.2	. 2 ⊢ (𝜑 → 𝐴 ⊆ 𝐶)
3		ssin 3298	. . 3 ⊢ ((𝐴 ⊆ 𝐵 ∧ 𝐴 ⊆ 𝐶) ↔ 𝐴 ⊆ (𝐵 ∩ 𝐶))
4	3	biimpi 119	. 2 ⊢ ((𝐴 ⊆ 𝐵 ∧ 𝐴 ⊆ 𝐶) → 𝐴 ⊆ (𝐵 ∩ 𝐶))
5	1, 2, 4	syl2anc 408	1 ⊢ (𝜑 → 𝐴 ⊆ (𝐵 ∩ 𝐶))

Syntax hints:   → wi 4   ∧ wa 103   ∩ cin 3070   ⊆ wss 3071

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-ia1 105  ax-ia2 106  ax-ia3 107  ax-io 698  ax-5 1423  ax-7 1424  ax-gen 1425  ax-ie1 1469  ax-ie2 1470  ax-8 1482  ax-10 1483  ax-11 1484  ax-i12 1485  ax-bndl 1486  ax-4 1487  ax-17 1506  ax-i9 1510  ax-ial 1514  ax-i5r 1515  ax-ext 2121

This theorem depends on definitions:  df-bi 116  df-tru 1334  df-nf 1437  df-sb 1736  df-clab 2126  df-cleq 2132  df-clel 2135  df-nfc 2270  df-v 2688  df-in 3077  df-ss 3084

This theorem is referenced by:  ntrin  12293  lmss  12415