| Step | Hyp | Ref | Expression | 
						
							| 1 |  | neg1cn |  |-  -u 1 e. CC | 
						
							| 2 |  | homulcl |  |-  ( ( -u 1 e. CC /\ U : ~H --> ~H ) -> ( -u 1 .op U ) : ~H --> ~H ) | 
						
							| 3 | 1 2 | mpan |  |-  ( U : ~H --> ~H -> ( -u 1 .op U ) : ~H --> ~H ) | 
						
							| 4 |  | hoadddi |  |-  ( ( A e. CC /\ T : ~H --> ~H /\ ( -u 1 .op U ) : ~H --> ~H ) -> ( A .op ( T +op ( -u 1 .op U ) ) ) = ( ( A .op T ) +op ( A .op ( -u 1 .op U ) ) ) ) | 
						
							| 5 | 3 4 | syl3an3 |  |-  ( ( A e. CC /\ T : ~H --> ~H /\ U : ~H --> ~H ) -> ( A .op ( T +op ( -u 1 .op U ) ) ) = ( ( A .op T ) +op ( A .op ( -u 1 .op U ) ) ) ) | 
						
							| 6 |  | homul12 |  |-  ( ( A e. CC /\ -u 1 e. CC /\ U : ~H --> ~H ) -> ( A .op ( -u 1 .op U ) ) = ( -u 1 .op ( A .op U ) ) ) | 
						
							| 7 | 1 6 | mp3an2 |  |-  ( ( A e. CC /\ U : ~H --> ~H ) -> ( A .op ( -u 1 .op U ) ) = ( -u 1 .op ( A .op U ) ) ) | 
						
							| 8 | 7 | 3adant2 |  |-  ( ( A e. CC /\ T : ~H --> ~H /\ U : ~H --> ~H ) -> ( A .op ( -u 1 .op U ) ) = ( -u 1 .op ( A .op U ) ) ) | 
						
							| 9 | 8 | oveq2d |  |-  ( ( A e. CC /\ T : ~H --> ~H /\ U : ~H --> ~H ) -> ( ( A .op T ) +op ( A .op ( -u 1 .op U ) ) ) = ( ( A .op T ) +op ( -u 1 .op ( A .op U ) ) ) ) | 
						
							| 10 | 5 9 | eqtrd |  |-  ( ( A e. CC /\ T : ~H --> ~H /\ U : ~H --> ~H ) -> ( A .op ( T +op ( -u 1 .op U ) ) ) = ( ( A .op T ) +op ( -u 1 .op ( A .op U ) ) ) ) | 
						
							| 11 |  | honegsub |  |-  ( ( T : ~H --> ~H /\ U : ~H --> ~H ) -> ( T +op ( -u 1 .op U ) ) = ( T -op U ) ) | 
						
							| 12 | 11 | oveq2d |  |-  ( ( T : ~H --> ~H /\ U : ~H --> ~H ) -> ( A .op ( T +op ( -u 1 .op U ) ) ) = ( A .op ( T -op U ) ) ) | 
						
							| 13 | 12 | 3adant1 |  |-  ( ( A e. CC /\ T : ~H --> ~H /\ U : ~H --> ~H ) -> ( A .op ( T +op ( -u 1 .op U ) ) ) = ( A .op ( T -op U ) ) ) | 
						
							| 14 |  | homulcl |  |-  ( ( A e. CC /\ T : ~H --> ~H ) -> ( A .op T ) : ~H --> ~H ) | 
						
							| 15 |  | homulcl |  |-  ( ( A e. CC /\ U : ~H --> ~H ) -> ( A .op U ) : ~H --> ~H ) | 
						
							| 16 |  | honegsub |  |-  ( ( ( A .op T ) : ~H --> ~H /\ ( A .op U ) : ~H --> ~H ) -> ( ( A .op T ) +op ( -u 1 .op ( A .op U ) ) ) = ( ( A .op T ) -op ( A .op U ) ) ) | 
						
							| 17 | 14 15 16 | syl2an |  |-  ( ( ( A e. CC /\ T : ~H --> ~H ) /\ ( A e. CC /\ U : ~H --> ~H ) ) -> ( ( A .op T ) +op ( -u 1 .op ( A .op U ) ) ) = ( ( A .op T ) -op ( A .op U ) ) ) | 
						
							| 18 | 17 | 3impdi |  |-  ( ( A e. CC /\ T : ~H --> ~H /\ U : ~H --> ~H ) -> ( ( A .op T ) +op ( -u 1 .op ( A .op U ) ) ) = ( ( A .op T ) -op ( A .op U ) ) ) | 
						
							| 19 | 10 13 18 | 3eqtr3d |  |-  ( ( A e. CC /\ T : ~H --> ~H /\ U : ~H --> ~H ) -> ( A .op ( T -op U ) ) = ( ( A .op T ) -op ( A .op U ) ) ) |