Theorem dfin5 3218

Description: Alternate definition for the intersection of two classes. (Contributed by NM, 6-Jul-2005.)

Assertion

Ref	Expression
dfin5	⊢ (𝐴 ∩ 𝐵) = {𝑥 ∈ 𝐴 ∣ 𝑥 ∈ 𝐵}

Distinct variable groups:   𝑥,𝐴   𝑥,𝐵

Proof of Theorem dfin5

Step	Hyp	Ref	Expression
1		df-in 3217	. 2 ⊢ (𝐴 ∩ 𝐵) = {𝑥 ∣ (𝑥 ∈ 𝐴 ∧ 𝑥 ∈ 𝐵)}
2		df-rab 2529	. 2 ⊢ {𝑥 ∈ 𝐴 ∣ 𝑥 ∈ 𝐵} = {𝑥 ∣ (𝑥 ∈ 𝐴 ∧ 𝑥 ∈ 𝐵)}
3	1, 2	eqtr4i 2256	1 ⊢ (𝐴 ∩ 𝐵) = {𝑥 ∈ 𝐴 ∣ 𝑥 ∈ 𝐵}

Syntax hints:   ∧ wa 104   = wceq 1398   ∈ wcel 2203  {cab 2218  {crab 2524   ∩ cin 3210

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-5 1496  ax-gen 1498  ax-4 1559  ax-17 1575  ax-ext 2214

This theorem depends on definitions:  df-bi 117  df-cleq 2225  df-rab 2529  df-in 3217

This theorem is referenced by:  nfin  3427  rabbi2dva  3429  ssfidc  7198  2omap  7269  2omapfi  7271  suprzubdc  10596  nninfdcex  10597  nnmindc  12730  nnminle  12731  znnen  13149  bj-inex  16677  pw1map  16769