Theorem ssind 3384

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 3382	. . 3 ⊢ ((𝐴 ⊆ 𝐵 ∧ 𝐴 ⊆ 𝐶) ↔ 𝐴 ⊆ (𝐵 ∩ 𝐶))
4	3	biimpi 120	. 2 ⊢ ((𝐴 ⊆ 𝐵 ∧ 𝐴 ⊆ 𝐶) → 𝐴 ⊆ (𝐵 ∩ 𝐶))
5	1, 2, 4	syl2anc 411	1 ⊢ (𝜑 → 𝐴 ⊆ (𝐵 ∩ 𝐶))

Syntax hints:   → wi 4   ∧ wa 104   ∩ cin 3153   ⊆ wss 3154

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-ia1 106  ax-ia2 107  ax-ia3 108  ax-io 710  ax-5 1458  ax-7 1459  ax-gen 1460  ax-ie1 1504  ax-ie2 1505  ax-8 1515  ax-10 1516  ax-11 1517  ax-i12 1518  ax-bndl 1520  ax-4 1521  ax-17 1537  ax-i9 1541  ax-ial 1545  ax-i5r 1546  ax-ext 2175

This theorem depends on definitions:  df-bi 117  df-tru 1367  df-nf 1472  df-sb 1774  df-clab 2180  df-cleq 2186  df-clel 2189  df-nfc 2325  df-v 2762  df-in 3160  df-ss 3167

This theorem is referenced by:  ntrin  14303  lmss  14425