Theorem lubsn 17094

Description: The least upper bound of a singleton. (chsupsn 28272 analog.) (Contributed by NM, 20-Oct-2011.)

Hypotheses

Ref	Expression
lubsn.b	|- B = ( Base ` K )
lubsn.u	|- U = ( lub ` K )

Assertion

Ref	Expression
lubsn	|- ( ( K e. Lat /\ X e. B ) -> ( U ` { X } ) = X )

Proof of Theorem lubsn

Step	Hyp	Ref	Expression
1		lubsn.u	. . . 4 |- U = ( lub ` K )
2		eqid 2622	. . . 4 |- ( join ` K ) = ( join ` K )
3		simpl 473	. . . 4 |- ( ( K e. Lat /\ X e. B ) -> K e. Lat )
4		simpr 477	. . . 4 |- ( ( K e. Lat /\ X e. B ) -> X e. B )
5	1, 2, 3, 4, 4	joinval 17005	. . 3 |- ( ( K e. Lat /\ X e. B ) -> ( X ( join ` K ) X ) = ( U ` { X , X } ) )
6		dfsn2 4190	. . . 4 |- { X } = { X , X }
7	6	fveq2i 6194	. . 3 |- ( U ` { X } ) = ( U ` { X , X } )
8	5, 7	syl6reqr 2675	. 2 |- ( ( K e. Lat /\ X e. B ) -> ( U ` { X } ) = ( X ( join ` K ) X ) )
9		lubsn.b	. . 3 |- B = ( Base ` K )
10	9, 2	latjidm 17074	. 2 |- ( ( K e. Lat /\ X e. B ) -> ( X ( join ` K ) X ) = X )
11	8, 10	eqtrd 2656	1 |- ( ( K e. Lat /\ X e. B ) -> ( U ` { X } ) = X )

Syntax hints:   -> wi 4   /\ wa 384   = wceq 1483   e. wcel 1990   {csn 4177   {cpr 4179   ` cfv 5888  (class class class)co 6650   Basecbs 15857   lubclub 16942   joincjn 16944   Latclat 17045

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-8 1992  ax-9 1999  ax-10 2019  ax-11 2034  ax-12 2047  ax-13 2246  ax-ext 2602  ax-rep 4771  ax-sep 4781  ax-nul 4789  ax-pow 4843  ax-pr 4906  ax-un 6949

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-eu 2474  df-mo 2475  df-clab 2609  df-cleq 2615  df-clel 2618  df-nfc 2753  df-ne 2795  df-ral 2917  df-rex 2918  df-reu 2919  df-rab 2921  df-v 3202  df-sbc 3436  df-csb 3534  df-dif 3577  df-un 3579  df-in 3581  df-ss 3588  df-nul 3916  df-if 4087  df-pw 4160  df-sn 4178  df-pr 4180  df-op 4184  df-uni 4437  df-iun 4522  df-br 4654  df-opab 4713  df-mpt 4730  df-id 5024  df-xp 5120  df-rel 5121  df-cnv 5122  df-co 5123  df-dm 5124  df-rn 5125  df-res 5126  df-ima 5127  df-iota 5851  df-fun 5890  df-fn 5891  df-f 5892  df-f1 5893  df-fo 5894  df-f1o 5895  df-fv 5896  df-riota 6611  df-ov 6653  df-oprab 6654  df-preset 16928  df-poset 16946  df-lub 16974  df-glb 16975  df-join 16976  df-meet 16977  df-lat 17046

This theorem is referenced by:  lubel  17122