| Step | Hyp | Ref | Expression | 
						
							| 1 |  | s2eqd.1 |  |-  ( ph -> A = N ) | 
						
							| 2 |  | s2eqd.2 |  |-  ( ph -> B = O ) | 
						
							| 3 |  | s3eqd.3 |  |-  ( ph -> C = P ) | 
						
							| 4 |  | s4eqd.4 |  |-  ( ph -> D = Q ) | 
						
							| 5 |  | s5eqd.5 |  |-  ( ph -> E = R ) | 
						
							| 6 |  | s6eqd.6 |  |-  ( ph -> F = S ) | 
						
							| 7 |  | s7eqd.6 |  |-  ( ph -> G = T ) | 
						
							| 8 |  | s8eqd.6 |  |-  ( ph -> H = U ) | 
						
							| 9 | 1 2 3 4 5 6 7 | s7eqd |  |-  ( ph -> <" A B C D E F G "> = <" N O P Q R S T "> ) | 
						
							| 10 | 8 | s1eqd |  |-  ( ph -> <" H "> = <" U "> ) | 
						
							| 11 | 9 10 | oveq12d |  |-  ( ph -> ( <" A B C D E F G "> ++ <" H "> ) = ( <" N O P Q R S T "> ++ <" U "> ) ) | 
						
							| 12 |  | df-s8 |  |-  <" A B C D E F G H "> = ( <" A B C D E F G "> ++ <" H "> ) | 
						
							| 13 |  | df-s8 |  |-  <" N O P Q R S T U "> = ( <" N O P Q R S T "> ++ <" U "> ) | 
						
							| 14 | 11 12 13 | 3eqtr4g |  |-  ( ph -> <" A B C D E F G H "> = <" N O P Q R S T U "> ) |