Theorem dfidk2 4314

Description: Definition of _I_k_k in terms of S_k. (Contributed by SF, 14-Jan-2015.)

Assertion

Ref	Expression
dfidk2	|- _I_kk = ( Sk i^i `'k Sk )

Proof of Theorem dfidk2

Dummy variables x y are mutually distinct and distinct from all other variables.

Step	Hyp	Ref	Expression
1		idkssvvk 4282	. 2 |- _I_kk C_ (_V X.k _V)
2		inss1 3476	. . 3 |- ( Sk i^i `'k Sk ) C_ Sk
3		ssetkssvvk 4279	. . 3 |- Sk C_ (_V X.k _V)
4	2, 3	sstri 3282	. 2 |- ( Sk i^i `'k Sk ) C_ (_V X.k _V)
5		eqss 3288	. . 3 |- (x = y <-> (x C_ y /\ y C_ x))
6		vex 2863	. . . 4 |- x e. _V
7		vex 2863	. . . 4 |- y e. _V
8		opkelidkg 4275	. . . 4 |- ((x e. _V /\ y e. _V) -> (<<x, y>> e. _I_kk <-> x = y))
9	6, 7, 8	mp2an 653	. . 3 |- (<<x, y>> e. _I_kk <-> x = y)
10		elin 3220	. . . 4 |- (<<x, y>> e. ( Sk i^i `'k Sk ) <-> (<<x, y>> e. Sk /\ <<x, y>> e. `'k Sk ))
11		opkelssetkg 4269	. . . . . 6 |- ((x e. _V /\ y e. _V) -> (<<x, y>> e. Sk <-> x C_ y))
12	6, 7, 11	mp2an 653	. . . . 5 |- (<<x, y>> e. Sk <-> x C_ y)
13	6, 7	opkelcnvk 4251	. . . . . 6 |- (<<x, y>> e. `'k Sk <-> <<y, x>> e. Sk )
14		opkelssetkg 4269	. . . . . . 7 |- ((y e. _V /\ x e. _V) -> (<<y, x>> e. Sk <-> y C_ x))
15	7, 6, 14	mp2an 653	. . . . . 6 |- (<<y, x>> e. Sk <-> y C_ x)
16	13, 15	bitri 240	. . . . 5 |- (<<x, y>> e. `'k Sk <-> y C_ x)
17	12, 16	anbi12i 678	. . . 4 |- ((<<x, y>> e. Sk /\ <<x, y>> e. `'k Sk ) <-> (x C_ y /\ y C_ x))
18	10, 17	bitri 240	. . 3 |- (<<x, y>> e. ( Sk i^i `'k Sk ) <-> (x C_ y /\ y C_ x))
19	5, 9, 18	3bitr4i 268	. 2 |- (<<x, y>> e. _I_kk <-> <<x, y>> e. ( Sk i^i `'k Sk ))
20	1, 4, 19	eqrelkriiv 4214	1 |- _I_kk = ( Sk i^i `'k Sk )

Syntax hints:   <-> wb 176   /\ wa 358   = wceq 1642   e. wcel 1710  _Vcvv 2860   i^i cin 3209   C_ wss 3258  <<copk 4058   X._k cxpk 4175  `'_kccnvk 4176   S_k cssetk 4184   _I_k_k cidk 4185

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1546  ax-5 1557  ax-17 1616  ax-9 1654  ax-8 1675  ax-6 1729  ax-7 1734  ax-11 1746  ax-12 1925  ax-ext 2334  ax-nin 4079  ax-sn 4088

This theorem depends on definitions:  df-bi 177  df-or 359  df-an 360  df-3an 936  df-nan 1288  df-tru 1319  df-ex 1542  df-nf 1545  df-sb 1649  df-clab 2340  df-cleq 2346  df-clel 2349  df-nfc 2479  df-ne 2519  df-ral 2620  df-v 2862  df-nin 3212  df-compl 3213  df-in 3214  df-un 3215  df-dif 3216  df-ss 3260  df-nul 3552  df-sn 3742  df-pr 3743  df-opk 4059  df-xpk 4186  df-cnvk 4187  df-ssetk 4194  df-idk 4196

This theorem is referenced by:  idkex  4315