| 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 ) |