Theorem intsn 4513

Description: The intersection of a singleton is its member. Theorem 70 of [Suppes] p. 41. (Contributed by NM, 29-Sep-2002.)

Hypothesis

Ref	Expression
intsn.1	|- A e. _V

Assertion

Ref	Expression
intsn	|- |^| { A } = A

Proof of Theorem intsn

Step	Hyp	Ref	Expression
1		intsn.1	. 2 |- A e. _V
2		intsng 4512	. 2 |- ( A e. _V -> |^| { A } = A )
3	1, 2	ax-mp 5	1 |- |^| { A } = A

Syntax hints:   = wceq 1483   e. wcel 1990   _Vcvv 3200   {csn 4177   |^|cint 4475

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1722  ax-4 1737  ax-5 1839  ax-6 1888  ax-7 1935  ax-9 1999  ax-10 2019  ax-11 2034  ax-12 2047  ax-13 2246  ax-ext 2602

This theorem depends on definitions:  df-bi 197  df-or 385  df-an 386  df-3an 1039  df-tru 1486  df-ex 1705  df-nf 1710  df-sb 1881  df-clab 2609  df-cleq 2615  df-clel 2618  df-nfc 2753  df-ral 2917  df-v 3202  df-un 3579  df-in 3581  df-sn 4178  df-pr 4180  df-int 4476

This theorem is referenced by:  uniintsn  4514  intunsn  4516  op1stb  4940  op2ndb  5619  ssfii  8325  cf0  9073  cflecard  9075  uffix  21725  iotain  38618