| Step | 
						Hyp | 
						Ref | 
						Expression | 
					
						
							| 1 | 
							
								
							 | 
							osumcllem.l | 
							 |-  .<_ = ( le ` K )  | 
						
						
							| 2 | 
							
								
							 | 
							osumcllem.j | 
							 |-  .\/ = ( join ` K )  | 
						
						
							| 3 | 
							
								
							 | 
							osumcllem.a | 
							 |-  A = ( Atoms ` K )  | 
						
						
							| 4 | 
							
								
							 | 
							osumcllem.p | 
							 |-  .+ = ( +P ` K )  | 
						
						
							| 5 | 
							
								
							 | 
							osumcllem.o | 
							 |-  ._|_ = ( _|_P ` K )  | 
						
						
							| 6 | 
							
								
							 | 
							osumcllem.c | 
							 |-  C = ( PSubCl ` K )  | 
						
						
							| 7 | 
							
								
							 | 
							osumcllem.m | 
							 |-  M = ( X .+ { p } ) | 
						
						
							| 8 | 
							
								
							 | 
							osumcllem.u | 
							 |-  U = ( ._|_ ` ( ._|_ ` ( X .+ Y ) ) )  | 
						
						
							| 9 | 
							
								3 4
							 | 
							sspadd1 | 
							 |-  ( ( K e. HL /\ X C_ A /\ Y C_ A ) -> X C_ ( X .+ Y ) )  | 
						
						
							| 10 | 
							
								9
							 | 
							adantr | 
							 |-  ( ( ( K e. HL /\ X C_ A /\ Y C_ A ) /\ p e. U ) -> X C_ ( X .+ Y ) )  | 
						
						
							| 11 | 
							
								
							 | 
							simpl1 | 
							 |-  ( ( ( K e. HL /\ X C_ A /\ Y C_ A ) /\ p e. U ) -> K e. HL )  | 
						
						
							| 12 | 
							
								3 4
							 | 
							paddssat | 
							 |-  ( ( K e. HL /\ X C_ A /\ Y C_ A ) -> ( X .+ Y ) C_ A )  | 
						
						
							| 13 | 
							
								12
							 | 
							adantr | 
							 |-  ( ( ( K e. HL /\ X C_ A /\ Y C_ A ) /\ p e. U ) -> ( X .+ Y ) C_ A )  | 
						
						
							| 14 | 
							
								3 5
							 | 
							2polssN | 
							 |-  ( ( K e. HL /\ ( X .+ Y ) C_ A ) -> ( X .+ Y ) C_ ( ._|_ ` ( ._|_ ` ( X .+ Y ) ) ) )  | 
						
						
							| 15 | 
							
								11 13 14
							 | 
							syl2anc | 
							 |-  ( ( ( K e. HL /\ X C_ A /\ Y C_ A ) /\ p e. U ) -> ( X .+ Y ) C_ ( ._|_ ` ( ._|_ ` ( X .+ Y ) ) ) )  | 
						
						
							| 16 | 
							
								15 8
							 | 
							sseqtrrdi | 
							 |-  ( ( ( K e. HL /\ X C_ A /\ Y C_ A ) /\ p e. U ) -> ( X .+ Y ) C_ U )  | 
						
						
							| 17 | 
							
								10 16
							 | 
							sstrd | 
							 |-  ( ( ( K e. HL /\ X C_ A /\ Y C_ A ) /\ p e. U ) -> X C_ U )  | 
						
						
							| 18 | 
							
								
							 | 
							simpr | 
							 |-  ( ( ( K e. HL /\ X C_ A /\ Y C_ A ) /\ p e. U ) -> p e. U )  | 
						
						
							| 19 | 
							
								18
							 | 
							snssd | 
							 |-  ( ( ( K e. HL /\ X C_ A /\ Y C_ A ) /\ p e. U ) -> { p } C_ U ) | 
						
						
							| 20 | 
							
								
							 | 
							simpl2 | 
							 |-  ( ( ( K e. HL /\ X C_ A /\ Y C_ A ) /\ p e. U ) -> X C_ A )  | 
						
						
							| 21 | 
							
								3 5
							 | 
							polssatN | 
							 |-  ( ( K e. HL /\ ( X .+ Y ) C_ A ) -> ( ._|_ ` ( X .+ Y ) ) C_ A )  | 
						
						
							| 22 | 
							
								11 13 21
							 | 
							syl2anc | 
							 |-  ( ( ( K e. HL /\ X C_ A /\ Y C_ A ) /\ p e. U ) -> ( ._|_ ` ( X .+ Y ) ) C_ A )  | 
						
						
							| 23 | 
							
								3 5
							 | 
							polssatN | 
							 |-  ( ( K e. HL /\ ( ._|_ ` ( X .+ Y ) ) C_ A ) -> ( ._|_ ` ( ._|_ ` ( X .+ Y ) ) ) C_ A )  | 
						
						
							| 24 | 
							
								11 22 23
							 | 
							syl2anc | 
							 |-  ( ( ( K e. HL /\ X C_ A /\ Y C_ A ) /\ p e. U ) -> ( ._|_ ` ( ._|_ ` ( X .+ Y ) ) ) C_ A )  | 
						
						
							| 25 | 
							
								8 24
							 | 
							eqsstrid | 
							 |-  ( ( ( K e. HL /\ X C_ A /\ Y C_ A ) /\ p e. U ) -> U C_ A )  | 
						
						
							| 26 | 
							
								19 25
							 | 
							sstrd | 
							 |-  ( ( ( K e. HL /\ X C_ A /\ Y C_ A ) /\ p e. U ) -> { p } C_ A ) | 
						
						
							| 27 | 
							
								
							 | 
							eqid | 
							 |-  ( PSubSp ` K ) = ( PSubSp ` K )  | 
						
						
							| 28 | 
							
								3 27 5
							 | 
							polsubN | 
							 |-  ( ( K e. HL /\ ( ._|_ ` ( X .+ Y ) ) C_ A ) -> ( ._|_ ` ( ._|_ ` ( X .+ Y ) ) ) e. ( PSubSp ` K ) )  | 
						
						
							| 29 | 
							
								11 22 28
							 | 
							syl2anc | 
							 |-  ( ( ( K e. HL /\ X C_ A /\ Y C_ A ) /\ p e. U ) -> ( ._|_ ` ( ._|_ ` ( X .+ Y ) ) ) e. ( PSubSp ` K ) )  | 
						
						
							| 30 | 
							
								8 29
							 | 
							eqeltrid | 
							 |-  ( ( ( K e. HL /\ X C_ A /\ Y C_ A ) /\ p e. U ) -> U e. ( PSubSp ` K ) )  | 
						
						
							| 31 | 
							
								3 27 4
							 | 
							paddss | 
							 |-  ( ( K e. HL /\ ( X C_ A /\ { p } C_ A /\ U e. ( PSubSp ` K ) ) ) -> ( ( X C_ U /\ { p } C_ U ) <-> ( X .+ { p } ) C_ U ) ) | 
						
						
							| 32 | 
							
								11 20 26 30 31
							 | 
							syl13anc | 
							 |-  ( ( ( K e. HL /\ X C_ A /\ Y C_ A ) /\ p e. U ) -> ( ( X C_ U /\ { p } C_ U ) <-> ( X .+ { p } ) C_ U ) ) | 
						
						
							| 33 | 
							
								17 19 32
							 | 
							mpbi2and | 
							 |-  ( ( ( K e. HL /\ X C_ A /\ Y C_ A ) /\ p e. U ) -> ( X .+ { p } ) C_ U ) | 
						
						
							| 34 | 
							
								7 33
							 | 
							eqsstrid | 
							 |-  ( ( ( K e. HL /\ X C_ A /\ Y C_ A ) /\ p e. U ) -> M C_ U )  | 
						
						
							| 35 | 
							
								
							 | 
							sseqin2 | 
							 |-  ( M C_ U <-> ( U i^i M ) = M )  | 
						
						
							| 36 | 
							
								34 35
							 | 
							sylib | 
							 |-  ( ( ( K e. HL /\ X C_ A /\ Y C_ A ) /\ p e. U ) -> ( U i^i M ) = M )  |