| Step | Hyp | Ref | Expression | 
						
							| 1 |  | chscl.1 |  |-  ( ph -> A e. CH ) | 
						
							| 2 |  | chscl.2 |  |-  ( ph -> B e. CH ) | 
						
							| 3 |  | chscl.3 |  |-  ( ph -> B C_ ( _|_ ` A ) ) | 
						
							| 4 |  | chscl.4 |  |-  ( ph -> H : NN --> ( A +H B ) ) | 
						
							| 5 |  | chscl.5 |  |-  ( ph -> H ~~>v u ) | 
						
							| 6 |  | chscl.6 |  |-  F = ( n e. NN |-> ( ( projh ` A ) ` ( H ` n ) ) ) | 
						
							| 7 |  | eqid |  |-  ( ( projh ` A ) ` ( H ` n ) ) = ( ( projh ` A ) ` ( H ` n ) ) | 
						
							| 8 | 1 | adantr |  |-  ( ( ph /\ n e. NN ) -> A e. CH ) | 
						
							| 9 | 4 | ffvelcdmda |  |-  ( ( ph /\ n e. NN ) -> ( H ` n ) e. ( A +H B ) ) | 
						
							| 10 |  | chsh |  |-  ( B e. CH -> B e. SH ) | 
						
							| 11 | 2 10 | syl |  |-  ( ph -> B e. SH ) | 
						
							| 12 |  | chsh |  |-  ( A e. CH -> A e. SH ) | 
						
							| 13 | 1 12 | syl |  |-  ( ph -> A e. SH ) | 
						
							| 14 |  | shocsh |  |-  ( A e. SH -> ( _|_ ` A ) e. SH ) | 
						
							| 15 | 13 14 | syl |  |-  ( ph -> ( _|_ ` A ) e. SH ) | 
						
							| 16 |  | shless |  |-  ( ( ( B e. SH /\ ( _|_ ` A ) e. SH /\ A e. SH ) /\ B C_ ( _|_ ` A ) ) -> ( B +H A ) C_ ( ( _|_ ` A ) +H A ) ) | 
						
							| 17 | 11 15 13 3 16 | syl31anc |  |-  ( ph -> ( B +H A ) C_ ( ( _|_ ` A ) +H A ) ) | 
						
							| 18 |  | shscom |  |-  ( ( A e. SH /\ B e. SH ) -> ( A +H B ) = ( B +H A ) ) | 
						
							| 19 | 13 11 18 | syl2anc |  |-  ( ph -> ( A +H B ) = ( B +H A ) ) | 
						
							| 20 |  | shscom |  |-  ( ( A e. SH /\ ( _|_ ` A ) e. SH ) -> ( A +H ( _|_ ` A ) ) = ( ( _|_ ` A ) +H A ) ) | 
						
							| 21 | 13 15 20 | syl2anc |  |-  ( ph -> ( A +H ( _|_ ` A ) ) = ( ( _|_ ` A ) +H A ) ) | 
						
							| 22 | 17 19 21 | 3sstr4d |  |-  ( ph -> ( A +H B ) C_ ( A +H ( _|_ ` A ) ) ) | 
						
							| 23 | 22 | sselda |  |-  ( ( ph /\ ( H ` n ) e. ( A +H B ) ) -> ( H ` n ) e. ( A +H ( _|_ ` A ) ) ) | 
						
							| 24 | 9 23 | syldan |  |-  ( ( ph /\ n e. NN ) -> ( H ` n ) e. ( A +H ( _|_ ` A ) ) ) | 
						
							| 25 |  | pjpreeq |  |-  ( ( A e. CH /\ ( H ` n ) e. ( A +H ( _|_ ` A ) ) ) -> ( ( ( projh ` A ) ` ( H ` n ) ) = ( ( projh ` A ) ` ( H ` n ) ) <-> ( ( ( projh ` A ) ` ( H ` n ) ) e. A /\ E. x e. ( _|_ ` A ) ( H ` n ) = ( ( ( projh ` A ) ` ( H ` n ) ) +h x ) ) ) ) | 
						
							| 26 | 8 24 25 | syl2anc |  |-  ( ( ph /\ n e. NN ) -> ( ( ( projh ` A ) ` ( H ` n ) ) = ( ( projh ` A ) ` ( H ` n ) ) <-> ( ( ( projh ` A ) ` ( H ` n ) ) e. A /\ E. x e. ( _|_ ` A ) ( H ` n ) = ( ( ( projh ` A ) ` ( H ` n ) ) +h x ) ) ) ) | 
						
							| 27 | 7 26 | mpbii |  |-  ( ( ph /\ n e. NN ) -> ( ( ( projh ` A ) ` ( H ` n ) ) e. A /\ E. x e. ( _|_ ` A ) ( H ` n ) = ( ( ( projh ` A ) ` ( H ` n ) ) +h x ) ) ) | 
						
							| 28 | 27 | simpld |  |-  ( ( ph /\ n e. NN ) -> ( ( projh ` A ) ` ( H ` n ) ) e. A ) | 
						
							| 29 | 28 6 | fmptd |  |-  ( ph -> F : NN --> A ) |