| Step | Hyp | Ref | Expression | 
						
							| 1 |  | s7rn.a |  |-  ( ph -> A e. V ) | 
						
							| 2 |  | s7rn.b |  |-  ( ph -> B e. V ) | 
						
							| 3 |  | s7rn.c |  |-  ( ph -> C e. V ) | 
						
							| 4 |  | s7rn.d |  |-  ( ph -> D e. V ) | 
						
							| 5 |  | s7rn.e |  |-  ( ph -> E e. V ) | 
						
							| 6 |  | s7rn.f |  |-  ( ph -> F e. V ) | 
						
							| 7 |  | s7rn.g |  |-  ( ph -> G e. V ) | 
						
							| 8 |  | s4s3 |  |-  <" A B C D E F G "> = ( <" A B C D "> ++ <" E F G "> ) | 
						
							| 9 | 8 | a1i |  |-  ( ph -> <" A B C D E F G "> = ( <" A B C D "> ++ <" E F G "> ) ) | 
						
							| 10 | 9 | rneqd |  |-  ( ph -> ran <" A B C D E F G "> = ran ( <" A B C D "> ++ <" E F G "> ) ) | 
						
							| 11 |  | s4cli |  |-  <" A B C D "> e. Word _V | 
						
							| 12 |  | s3cli |  |-  <" E F G "> e. Word _V | 
						
							| 13 | 11 12 | pm3.2i |  |-  ( <" A B C D "> e. Word _V /\ <" E F G "> e. Word _V ) | 
						
							| 14 |  | ccatrn |  |-  ( ( <" A B C D "> e. Word _V /\ <" E F G "> e. Word _V ) -> ran ( <" A B C D "> ++ <" E F G "> ) = ( ran <" A B C D "> u. ran <" E F G "> ) ) | 
						
							| 15 | 13 14 | mp1i |  |-  ( ph -> ran ( <" A B C D "> ++ <" E F G "> ) = ( ran <" A B C D "> u. ran <" E F G "> ) ) | 
						
							| 16 |  | df-s4 |  |-  <" A B C D "> = ( <" A B C "> ++ <" D "> ) | 
						
							| 17 | 16 | a1i |  |-  ( ph -> <" A B C D "> = ( <" A B C "> ++ <" D "> ) ) | 
						
							| 18 | 17 | rneqd |  |-  ( ph -> ran <" A B C D "> = ran ( <" A B C "> ++ <" D "> ) ) | 
						
							| 19 |  | s3cli |  |-  <" A B C "> e. Word _V | 
						
							| 20 |  | s1cli |  |-  <" D "> e. Word _V | 
						
							| 21 | 19 20 | pm3.2i |  |-  ( <" A B C "> e. Word _V /\ <" D "> e. Word _V ) | 
						
							| 22 |  | ccatrn |  |-  ( ( <" A B C "> e. Word _V /\ <" D "> e. Word _V ) -> ran ( <" A B C "> ++ <" D "> ) = ( ran <" A B C "> u. ran <" D "> ) ) | 
						
							| 23 | 21 22 | mp1i |  |-  ( ph -> ran ( <" A B C "> ++ <" D "> ) = ( ran <" A B C "> u. ran <" D "> ) ) | 
						
							| 24 | 1 2 3 | s3rn |  |-  ( ph -> ran <" A B C "> = { A , B , C } ) | 
						
							| 25 |  | s1rn |  |-  ( D e. V -> ran <" D "> = { D } ) | 
						
							| 26 | 4 25 | syl |  |-  ( ph -> ran <" D "> = { D } ) | 
						
							| 27 | 24 26 | uneq12d |  |-  ( ph -> ( ran <" A B C "> u. ran <" D "> ) = ( { A , B , C } u. { D } ) ) | 
						
							| 28 | 18 23 27 | 3eqtrd |  |-  ( ph -> ran <" A B C D "> = ( { A , B , C } u. { D } ) ) | 
						
							| 29 | 5 6 7 | s3rn |  |-  ( ph -> ran <" E F G "> = { E , F , G } ) | 
						
							| 30 | 28 29 | uneq12d |  |-  ( ph -> ( ran <" A B C D "> u. ran <" E F G "> ) = ( ( { A , B , C } u. { D } ) u. { E , F , G } ) ) | 
						
							| 31 | 10 15 30 | 3eqtrd |  |-  ( ph -> ran <" A B C D E F G "> = ( ( { A , B , C } u. { D } ) u. { E , F , G } ) ) |