Theorem dmsnop 6167

Description: The domain of a singleton of an ordered pair is the singleton of the first member. (Contributed by NM, 30-Jan-2004.) (Proof shortened by Andrew Salmon, 27-Aug-2011.) (Revised by Mario Carneiro, 26-Apr-2015.)

Hypothesis

Ref	Expression
dmsnop.1	⊢ 𝐵 ∈ V

Assertion

Ref	Expression
dmsnop	⊢ dom {⟨𝐴, 𝐵⟩} = {𝐴}

Proof of Theorem dmsnop

Step	Hyp	Ref	Expression
1		dmsnop.1	. 2 ⊢ 𝐵 ∈ V
2		dmsnopg 6164	. 2 ⊢ (𝐵 ∈ V → dom {⟨𝐴, 𝐵⟩} = {𝐴})
3	1, 2	ax-mp 5	1 ⊢ dom {⟨𝐴, 𝐵⟩} = {𝐴}

Syntax hints:   = wceq 1547   ∈ wcel 2119  Vcvv 3431  {csn 4555  ⟨cop 4561  dom cdm 5618

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1802  ax-4 1816  ax-5 1917  ax-6 1974  ax-7 2015  ax-8 2121  ax-9 2129  ax-ext 2711  ax-sep 5218  ax-pr 5362

This theorem depends on definitions:  df-bi 208  df-an 397  df-or 854  df-3an 1094  df-tru 1550  df-fal 1560  df-ex 1787  df-sb 2074  df-clab 2718  df-cleq 2731  df-clel 2814  df-rab 3392  df-v 3433  df-dif 3886  df-un 3888  df-in 3890  df-ss 3900  df-nul 4262  df-if 4455  df-sn 4556  df-pr 4558  df-op 4562  df-br 5073  df-dm 5628

This theorem is referenced by:  dmtpop  6169  dmsnsnsn  6171  op1sta  6176  snres0  6249  funtp  6542  funopdmsn  7093  frrlem14  8239  tfrlem10  8316  ac6sfi  9184  dcomex  10360  axdc3lem4  10366  cnfldfunALT  21362  noextend  27648  nosupbday  27687  nosupbnd1  27696  nosupbnd2  27698  noinfbday  27702  noinfbnd1  27711  noinfbnd2  27713  bnj1416  35221  bnj1421  35224  fineqvac  35297  subfacp1lem2a  35408  subfacp1lem5  35412