Theorem inin 32537

Description: Intersection with an intersection. (Contributed by Thierry Arnoux, 27-Dec-2016.)

Assertion

Ref	Expression
inin	⊢ (𝐴 ∩ (𝐴 ∩ 𝐵)) = (𝐴 ∩ 𝐵)

Proof of Theorem inin

Step	Hyp	Ref	Expression
1		in13 4252	. 2 ⊢ (𝐴 ∩ (𝐴 ∩ 𝐵)) = (𝐵 ∩ (𝐴 ∩ 𝐴))
2		inidm 4248	. . 3 ⊢ (𝐴 ∩ 𝐴) = 𝐴
3	2	ineq2i 4238	. 2 ⊢ (𝐵 ∩ (𝐴 ∩ 𝐴)) = (𝐵 ∩ 𝐴)
4		incom 4230	. 2 ⊢ (𝐵 ∩ 𝐴) = (𝐴 ∩ 𝐵)
5	1, 3, 4	3eqtri 2772	1 ⊢ (𝐴 ∩ (𝐴 ∩ 𝐵)) = (𝐴 ∩ 𝐵)

Syntax hints:   = wceq 1537   ∩ cin 3975

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1793  ax-4 1807  ax-5 1909  ax-6 1967  ax-7 2007  ax-8 2110  ax-9 2118  ax-ext 2711

This theorem depends on definitions:  df-bi 207  df-an 396  df-tru 1540  df-ex 1778  df-sb 2065  df-clab 2718  df-cleq 2732  df-clel 2819  df-rab 3444  df-v 3490  df-in 3983

This theorem is referenced by:  measinb2  34179