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Description: The range of a concatenated word. (Contributed by Stefan O'Rear, 15-Aug-2015)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | ccatrn | |- ( ( S e. Word B /\ T e. Word B ) -> ran ( S ++ T ) = ( ran S u. ran T ) ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | ccatvalfn | |- ( ( S e. Word B /\ T e. Word B ) -> ( S ++ T ) Fn ( 0 ..^ ( ( # ` S ) + ( # ` T ) ) ) ) |
|
| 2 | lencl | |- ( S e. Word B -> ( # ` S ) e. NN0 ) |
|
| 3 | nn0uz | |- NN0 = ( ZZ>= ` 0 ) |
|
| 4 | 2 3 | eleqtrdi | |- ( S e. Word B -> ( # ` S ) e. ( ZZ>= ` 0 ) ) |
| 5 | 4 | adantr | |- ( ( S e. Word B /\ T e. Word B ) -> ( # ` S ) e. ( ZZ>= ` 0 ) ) |
| 6 | 2 | nn0zd | |- ( S e. Word B -> ( # ` S ) e. ZZ ) |
| 7 | 6 | uzidd | |- ( S e. Word B -> ( # ` S ) e. ( ZZ>= ` ( # ` S ) ) ) |
| 8 | lencl | |- ( T e. Word B -> ( # ` T ) e. NN0 ) |
|
| 9 | uzaddcl | |- ( ( ( # ` S ) e. ( ZZ>= ` ( # ` S ) ) /\ ( # ` T ) e. NN0 ) -> ( ( # ` S ) + ( # ` T ) ) e. ( ZZ>= ` ( # ` S ) ) ) |
|
| 10 | 7 8 9 | syl2an | |- ( ( S e. Word B /\ T e. Word B ) -> ( ( # ` S ) + ( # ` T ) ) e. ( ZZ>= ` ( # ` S ) ) ) |
| 11 | elfzuzb | |- ( ( # ` S ) e. ( 0 ... ( ( # ` S ) + ( # ` T ) ) ) <-> ( ( # ` S ) e. ( ZZ>= ` 0 ) /\ ( ( # ` S ) + ( # ` T ) ) e. ( ZZ>= ` ( # ` S ) ) ) ) |
|
| 12 | 5 10 11 | sylanbrc | |- ( ( S e. Word B /\ T e. Word B ) -> ( # ` S ) e. ( 0 ... ( ( # ` S ) + ( # ` T ) ) ) ) |
| 13 | fzosplit | |- ( ( # ` S ) e. ( 0 ... ( ( # ` S ) + ( # ` T ) ) ) -> ( 0 ..^ ( ( # ` S ) + ( # ` T ) ) ) = ( ( 0 ..^ ( # ` S ) ) u. ( ( # ` S ) ..^ ( ( # ` S ) + ( # ` T ) ) ) ) ) |
|
| 14 | 12 13 | syl | |- ( ( S e. Word B /\ T e. Word B ) -> ( 0 ..^ ( ( # ` S ) + ( # ` T ) ) ) = ( ( 0 ..^ ( # ` S ) ) u. ( ( # ` S ) ..^ ( ( # ` S ) + ( # ` T ) ) ) ) ) |
| 15 | 14 | eleq2d | |- ( ( S e. Word B /\ T e. Word B ) -> ( x e. ( 0 ..^ ( ( # ` S ) + ( # ` T ) ) ) <-> x e. ( ( 0 ..^ ( # ` S ) ) u. ( ( # ` S ) ..^ ( ( # ` S ) + ( # ` T ) ) ) ) ) ) |
| 16 | elun | |- ( x e. ( ( 0 ..^ ( # ` S ) ) u. ( ( # ` S ) ..^ ( ( # ` S ) + ( # ` T ) ) ) ) <-> ( x e. ( 0 ..^ ( # ` S ) ) \/ x e. ( ( # ` S ) ..^ ( ( # ` S ) + ( # ` T ) ) ) ) ) |
|
| 17 | 15 16 | bitrdi | |- ( ( S e. Word B /\ T e. Word B ) -> ( x e. ( 0 ..^ ( ( # ` S ) + ( # ` T ) ) ) <-> ( x e. ( 0 ..^ ( # ` S ) ) \/ x e. ( ( # ` S ) ..^ ( ( # ` S ) + ( # ` T ) ) ) ) ) ) |
| 18 | ccatval1 | |- ( ( S e. Word B /\ T e. Word B /\ x e. ( 0 ..^ ( # ` S ) ) ) -> ( ( S ++ T ) ` x ) = ( S ` x ) ) |
|
| 19 | 18 | 3expa | |- ( ( ( S e. Word B /\ T e. Word B ) /\ x e. ( 0 ..^ ( # ` S ) ) ) -> ( ( S ++ T ) ` x ) = ( S ` x ) ) |
| 20 | ssun1 | |- ran S C_ ( ran S u. ran T ) |
|
| 21 | wrdfn | |- ( S e. Word B -> S Fn ( 0 ..^ ( # ` S ) ) ) |
|
| 22 | 21 | adantr | |- ( ( S e. Word B /\ T e. Word B ) -> S Fn ( 0 ..^ ( # ` S ) ) ) |
| 23 | fnfvelrn | |- ( ( S Fn ( 0 ..^ ( # ` S ) ) /\ x e. ( 0 ..^ ( # ` S ) ) ) -> ( S ` x ) e. ran S ) |
|
| 24 | 22 23 | sylan | |- ( ( ( S e. Word B /\ T e. Word B ) /\ x e. ( 0 ..^ ( # ` S ) ) ) -> ( S ` x ) e. ran S ) |
| 25 | 20 24 | sselid | |- ( ( ( S e. Word B /\ T e. Word B ) /\ x e. ( 0 ..^ ( # ` S ) ) ) -> ( S ` x ) e. ( ran S u. ran T ) ) |
| 26 | 19 25 | eqeltrd | |- ( ( ( S e. Word B /\ T e. Word B ) /\ x e. ( 0 ..^ ( # ` S ) ) ) -> ( ( S ++ T ) ` x ) e. ( ran S u. ran T ) ) |
| 27 | ccatval2 | |- ( ( S e. Word B /\ T e. Word B /\ x e. ( ( # ` S ) ..^ ( ( # ` S ) + ( # ` T ) ) ) ) -> ( ( S ++ T ) ` x ) = ( T ` ( x - ( # ` S ) ) ) ) |
|
| 28 | 27 | 3expa | |- ( ( ( S e. Word B /\ T e. Word B ) /\ x e. ( ( # ` S ) ..^ ( ( # ` S ) + ( # ` T ) ) ) ) -> ( ( S ++ T ) ` x ) = ( T ` ( x - ( # ` S ) ) ) ) |
| 29 | ssun2 | |- ran T C_ ( ran S u. ran T ) |
|
| 30 | wrdfn | |- ( T e. Word B -> T Fn ( 0 ..^ ( # ` T ) ) ) |
|
| 31 | 30 | adantl | |- ( ( S e. Word B /\ T e. Word B ) -> T Fn ( 0 ..^ ( # ` T ) ) ) |
| 32 | elfzouz | |- ( x e. ( ( # ` S ) ..^ ( ( # ` S ) + ( # ` T ) ) ) -> x e. ( ZZ>= ` ( # ` S ) ) ) |
|
| 33 | uznn0sub | |- ( x e. ( ZZ>= ` ( # ` S ) ) -> ( x - ( # ` S ) ) e. NN0 ) |
|
| 34 | 32 33 | syl | |- ( x e. ( ( # ` S ) ..^ ( ( # ` S ) + ( # ` T ) ) ) -> ( x - ( # ` S ) ) e. NN0 ) |
| 35 | 34 3 | eleqtrdi | |- ( x e. ( ( # ` S ) ..^ ( ( # ` S ) + ( # ` T ) ) ) -> ( x - ( # ` S ) ) e. ( ZZ>= ` 0 ) ) |
| 36 | 35 | adantl | |- ( ( ( S e. Word B /\ T e. Word B ) /\ x e. ( ( # ` S ) ..^ ( ( # ` S ) + ( # ` T ) ) ) ) -> ( x - ( # ` S ) ) e. ( ZZ>= ` 0 ) ) |
| 37 | 8 | nn0zd | |- ( T e. Word B -> ( # ` T ) e. ZZ ) |
| 38 | 37 | ad2antlr | |- ( ( ( S e. Word B /\ T e. Word B ) /\ x e. ( ( # ` S ) ..^ ( ( # ` S ) + ( # ` T ) ) ) ) -> ( # ` T ) e. ZZ ) |
| 39 | elfzolt2 | |- ( x e. ( ( # ` S ) ..^ ( ( # ` S ) + ( # ` T ) ) ) -> x < ( ( # ` S ) + ( # ` T ) ) ) |
|
| 40 | 39 | adantl | |- ( ( ( S e. Word B /\ T e. Word B ) /\ x e. ( ( # ` S ) ..^ ( ( # ` S ) + ( # ` T ) ) ) ) -> x < ( ( # ` S ) + ( # ` T ) ) ) |
| 41 | elfzoelz | |- ( x e. ( ( # ` S ) ..^ ( ( # ` S ) + ( # ` T ) ) ) -> x e. ZZ ) |
|
| 42 | 41 | zred | |- ( x e. ( ( # ` S ) ..^ ( ( # ` S ) + ( # ` T ) ) ) -> x e. RR ) |
| 43 | 42 | adantl | |- ( ( ( S e. Word B /\ T e. Word B ) /\ x e. ( ( # ` S ) ..^ ( ( # ` S ) + ( # ` T ) ) ) ) -> x e. RR ) |
| 44 | 2 | nn0red | |- ( S e. Word B -> ( # ` S ) e. RR ) |
| 45 | 44 | ad2antrr | |- ( ( ( S e. Word B /\ T e. Word B ) /\ x e. ( ( # ` S ) ..^ ( ( # ` S ) + ( # ` T ) ) ) ) -> ( # ` S ) e. RR ) |
| 46 | 8 | nn0red | |- ( T e. Word B -> ( # ` T ) e. RR ) |
| 47 | 46 | ad2antlr | |- ( ( ( S e. Word B /\ T e. Word B ) /\ x e. ( ( # ` S ) ..^ ( ( # ` S ) + ( # ` T ) ) ) ) -> ( # ` T ) e. RR ) |
| 48 | 43 45 47 | ltsubadd2d | |- ( ( ( S e. Word B /\ T e. Word B ) /\ x e. ( ( # ` S ) ..^ ( ( # ` S ) + ( # ` T ) ) ) ) -> ( ( x - ( # ` S ) ) < ( # ` T ) <-> x < ( ( # ` S ) + ( # ` T ) ) ) ) |
| 49 | 40 48 | mpbird | |- ( ( ( S e. Word B /\ T e. Word B ) /\ x e. ( ( # ` S ) ..^ ( ( # ` S ) + ( # ` T ) ) ) ) -> ( x - ( # ` S ) ) < ( # ` T ) ) |
| 50 | elfzo2 | |- ( ( x - ( # ` S ) ) e. ( 0 ..^ ( # ` T ) ) <-> ( ( x - ( # ` S ) ) e. ( ZZ>= ` 0 ) /\ ( # ` T ) e. ZZ /\ ( x - ( # ` S ) ) < ( # ` T ) ) ) |
|
| 51 | 36 38 49 50 | syl3anbrc | |- ( ( ( S e. Word B /\ T e. Word B ) /\ x e. ( ( # ` S ) ..^ ( ( # ` S ) + ( # ` T ) ) ) ) -> ( x - ( # ` S ) ) e. ( 0 ..^ ( # ` T ) ) ) |
| 52 | fnfvelrn | |- ( ( T Fn ( 0 ..^ ( # ` T ) ) /\ ( x - ( # ` S ) ) e. ( 0 ..^ ( # ` T ) ) ) -> ( T ` ( x - ( # ` S ) ) ) e. ran T ) |
|
| 53 | 31 51 52 | syl2an2r | |- ( ( ( S e. Word B /\ T e. Word B ) /\ x e. ( ( # ` S ) ..^ ( ( # ` S ) + ( # ` T ) ) ) ) -> ( T ` ( x - ( # ` S ) ) ) e. ran T ) |
| 54 | 29 53 | sselid | |- ( ( ( S e. Word B /\ T e. Word B ) /\ x e. ( ( # ` S ) ..^ ( ( # ` S ) + ( # ` T ) ) ) ) -> ( T ` ( x - ( # ` S ) ) ) e. ( ran S u. ran T ) ) |
| 55 | 28 54 | eqeltrd | |- ( ( ( S e. Word B /\ T e. Word B ) /\ x e. ( ( # ` S ) ..^ ( ( # ` S ) + ( # ` T ) ) ) ) -> ( ( S ++ T ) ` x ) e. ( ran S u. ran T ) ) |
| 56 | 26 55 | jaodan | |- ( ( ( S e. Word B /\ T e. Word B ) /\ ( x e. ( 0 ..^ ( # ` S ) ) \/ x e. ( ( # ` S ) ..^ ( ( # ` S ) + ( # ` T ) ) ) ) ) -> ( ( S ++ T ) ` x ) e. ( ran S u. ran T ) ) |
| 57 | 56 | ex | |- ( ( S e. Word B /\ T e. Word B ) -> ( ( x e. ( 0 ..^ ( # ` S ) ) \/ x e. ( ( # ` S ) ..^ ( ( # ` S ) + ( # ` T ) ) ) ) -> ( ( S ++ T ) ` x ) e. ( ran S u. ran T ) ) ) |
| 58 | 17 57 | sylbid | |- ( ( S e. Word B /\ T e. Word B ) -> ( x e. ( 0 ..^ ( ( # ` S ) + ( # ` T ) ) ) -> ( ( S ++ T ) ` x ) e. ( ran S u. ran T ) ) ) |
| 59 | 58 | ralrimiv | |- ( ( S e. Word B /\ T e. Word B ) -> A. x e. ( 0 ..^ ( ( # ` S ) + ( # ` T ) ) ) ( ( S ++ T ) ` x ) e. ( ran S u. ran T ) ) |
| 60 | ffnfv | |- ( ( S ++ T ) : ( 0 ..^ ( ( # ` S ) + ( # ` T ) ) ) --> ( ran S u. ran T ) <-> ( ( S ++ T ) Fn ( 0 ..^ ( ( # ` S ) + ( # ` T ) ) ) /\ A. x e. ( 0 ..^ ( ( # ` S ) + ( # ` T ) ) ) ( ( S ++ T ) ` x ) e. ( ran S u. ran T ) ) ) |
|
| 61 | 1 59 60 | sylanbrc | |- ( ( S e. Word B /\ T e. Word B ) -> ( S ++ T ) : ( 0 ..^ ( ( # ` S ) + ( # ` T ) ) ) --> ( ran S u. ran T ) ) |
| 62 | 61 | frnd | |- ( ( S e. Word B /\ T e. Word B ) -> ran ( S ++ T ) C_ ( ran S u. ran T ) ) |
| 63 | fzoss2 | |- ( ( ( # ` S ) + ( # ` T ) ) e. ( ZZ>= ` ( # ` S ) ) -> ( 0 ..^ ( # ` S ) ) C_ ( 0 ..^ ( ( # ` S ) + ( # ` T ) ) ) ) |
|
| 64 | 10 63 | syl | |- ( ( S e. Word B /\ T e. Word B ) -> ( 0 ..^ ( # ` S ) ) C_ ( 0 ..^ ( ( # ` S ) + ( # ` T ) ) ) ) |
| 65 | 64 | sselda | |- ( ( ( S e. Word B /\ T e. Word B ) /\ x e. ( 0 ..^ ( # ` S ) ) ) -> x e. ( 0 ..^ ( ( # ` S ) + ( # ` T ) ) ) ) |
| 66 | fnfvelrn | |- ( ( ( S ++ T ) Fn ( 0 ..^ ( ( # ` S ) + ( # ` T ) ) ) /\ x e. ( 0 ..^ ( ( # ` S ) + ( # ` T ) ) ) ) -> ( ( S ++ T ) ` x ) e. ran ( S ++ T ) ) |
|
| 67 | 1 65 66 | syl2an2r | |- ( ( ( S e. Word B /\ T e. Word B ) /\ x e. ( 0 ..^ ( # ` S ) ) ) -> ( ( S ++ T ) ` x ) e. ran ( S ++ T ) ) |
| 68 | 19 67 | eqeltrrd | |- ( ( ( S e. Word B /\ T e. Word B ) /\ x e. ( 0 ..^ ( # ` S ) ) ) -> ( S ` x ) e. ran ( S ++ T ) ) |
| 69 | 68 | ralrimiva | |- ( ( S e. Word B /\ T e. Word B ) -> A. x e. ( 0 ..^ ( # ` S ) ) ( S ` x ) e. ran ( S ++ T ) ) |
| 70 | ffnfv | |- ( S : ( 0 ..^ ( # ` S ) ) --> ran ( S ++ T ) <-> ( S Fn ( 0 ..^ ( # ` S ) ) /\ A. x e. ( 0 ..^ ( # ` S ) ) ( S ` x ) e. ran ( S ++ T ) ) ) |
|
| 71 | 22 69 70 | sylanbrc | |- ( ( S e. Word B /\ T e. Word B ) -> S : ( 0 ..^ ( # ` S ) ) --> ran ( S ++ T ) ) |
| 72 | 71 | frnd | |- ( ( S e. Word B /\ T e. Word B ) -> ran S C_ ran ( S ++ T ) ) |
| 73 | ccatval3 | |- ( ( S e. Word B /\ T e. Word B /\ x e. ( 0 ..^ ( # ` T ) ) ) -> ( ( S ++ T ) ` ( x + ( # ` S ) ) ) = ( T ` x ) ) |
|
| 74 | 73 | 3expa | |- ( ( ( S e. Word B /\ T e. Word B ) /\ x e. ( 0 ..^ ( # ` T ) ) ) -> ( ( S ++ T ) ` ( x + ( # ` S ) ) ) = ( T ` x ) ) |
| 75 | elfzouz | |- ( x e. ( 0 ..^ ( # ` T ) ) -> x e. ( ZZ>= ` 0 ) ) |
|
| 76 | 2 | adantr | |- ( ( S e. Word B /\ T e. Word B ) -> ( # ` S ) e. NN0 ) |
| 77 | uzaddcl | |- ( ( x e. ( ZZ>= ` 0 ) /\ ( # ` S ) e. NN0 ) -> ( x + ( # ` S ) ) e. ( ZZ>= ` 0 ) ) |
|
| 78 | 75 76 77 | syl2anr | |- ( ( ( S e. Word B /\ T e. Word B ) /\ x e. ( 0 ..^ ( # ` T ) ) ) -> ( x + ( # ` S ) ) e. ( ZZ>= ` 0 ) ) |
| 79 | nn0addcl | |- ( ( ( # ` S ) e. NN0 /\ ( # ` T ) e. NN0 ) -> ( ( # ` S ) + ( # ` T ) ) e. NN0 ) |
|
| 80 | 2 8 79 | syl2an | |- ( ( S e. Word B /\ T e. Word B ) -> ( ( # ` S ) + ( # ` T ) ) e. NN0 ) |
| 81 | 80 | nn0zd | |- ( ( S e. Word B /\ T e. Word B ) -> ( ( # ` S ) + ( # ` T ) ) e. ZZ ) |
| 82 | 81 | adantr | |- ( ( ( S e. Word B /\ T e. Word B ) /\ x e. ( 0 ..^ ( # ` T ) ) ) -> ( ( # ` S ) + ( # ` T ) ) e. ZZ ) |
| 83 | elfzonn0 | |- ( x e. ( 0 ..^ ( # ` T ) ) -> x e. NN0 ) |
|
| 84 | 83 | nn0cnd | |- ( x e. ( 0 ..^ ( # ` T ) ) -> x e. CC ) |
| 85 | 2 | nn0cnd | |- ( S e. Word B -> ( # ` S ) e. CC ) |
| 86 | 85 | adantr | |- ( ( S e. Word B /\ T e. Word B ) -> ( # ` S ) e. CC ) |
| 87 | addcom | |- ( ( x e. CC /\ ( # ` S ) e. CC ) -> ( x + ( # ` S ) ) = ( ( # ` S ) + x ) ) |
|
| 88 | 84 86 87 | syl2anr | |- ( ( ( S e. Word B /\ T e. Word B ) /\ x e. ( 0 ..^ ( # ` T ) ) ) -> ( x + ( # ` S ) ) = ( ( # ` S ) + x ) ) |
| 89 | 83 | nn0red | |- ( x e. ( 0 ..^ ( # ` T ) ) -> x e. RR ) |
| 90 | 89 | adantl | |- ( ( ( S e. Word B /\ T e. Word B ) /\ x e. ( 0 ..^ ( # ` T ) ) ) -> x e. RR ) |
| 91 | 46 | ad2antlr | |- ( ( ( S e. Word B /\ T e. Word B ) /\ x e. ( 0 ..^ ( # ` T ) ) ) -> ( # ` T ) e. RR ) |
| 92 | 44 | ad2antrr | |- ( ( ( S e. Word B /\ T e. Word B ) /\ x e. ( 0 ..^ ( # ` T ) ) ) -> ( # ` S ) e. RR ) |
| 93 | elfzolt2 | |- ( x e. ( 0 ..^ ( # ` T ) ) -> x < ( # ` T ) ) |
|
| 94 | 93 | adantl | |- ( ( ( S e. Word B /\ T e. Word B ) /\ x e. ( 0 ..^ ( # ` T ) ) ) -> x < ( # ` T ) ) |
| 95 | 90 91 92 94 | ltadd2dd | |- ( ( ( S e. Word B /\ T e. Word B ) /\ x e. ( 0 ..^ ( # ` T ) ) ) -> ( ( # ` S ) + x ) < ( ( # ` S ) + ( # ` T ) ) ) |
| 96 | 88 95 | eqbrtrd | |- ( ( ( S e. Word B /\ T e. Word B ) /\ x e. ( 0 ..^ ( # ` T ) ) ) -> ( x + ( # ` S ) ) < ( ( # ` S ) + ( # ` T ) ) ) |
| 97 | elfzo2 | |- ( ( x + ( # ` S ) ) e. ( 0 ..^ ( ( # ` S ) + ( # ` T ) ) ) <-> ( ( x + ( # ` S ) ) e. ( ZZ>= ` 0 ) /\ ( ( # ` S ) + ( # ` T ) ) e. ZZ /\ ( x + ( # ` S ) ) < ( ( # ` S ) + ( # ` T ) ) ) ) |
|
| 98 | 78 82 96 97 | syl3anbrc | |- ( ( ( S e. Word B /\ T e. Word B ) /\ x e. ( 0 ..^ ( # ` T ) ) ) -> ( x + ( # ` S ) ) e. ( 0 ..^ ( ( # ` S ) + ( # ` T ) ) ) ) |
| 99 | fnfvelrn | |- ( ( ( S ++ T ) Fn ( 0 ..^ ( ( # ` S ) + ( # ` T ) ) ) /\ ( x + ( # ` S ) ) e. ( 0 ..^ ( ( # ` S ) + ( # ` T ) ) ) ) -> ( ( S ++ T ) ` ( x + ( # ` S ) ) ) e. ran ( S ++ T ) ) |
|
| 100 | 1 98 99 | syl2an2r | |- ( ( ( S e. Word B /\ T e. Word B ) /\ x e. ( 0 ..^ ( # ` T ) ) ) -> ( ( S ++ T ) ` ( x + ( # ` S ) ) ) e. ran ( S ++ T ) ) |
| 101 | 74 100 | eqeltrrd | |- ( ( ( S e. Word B /\ T e. Word B ) /\ x e. ( 0 ..^ ( # ` T ) ) ) -> ( T ` x ) e. ran ( S ++ T ) ) |
| 102 | 101 | ralrimiva | |- ( ( S e. Word B /\ T e. Word B ) -> A. x e. ( 0 ..^ ( # ` T ) ) ( T ` x ) e. ran ( S ++ T ) ) |
| 103 | ffnfv | |- ( T : ( 0 ..^ ( # ` T ) ) --> ran ( S ++ T ) <-> ( T Fn ( 0 ..^ ( # ` T ) ) /\ A. x e. ( 0 ..^ ( # ` T ) ) ( T ` x ) e. ran ( S ++ T ) ) ) |
|
| 104 | 31 102 103 | sylanbrc | |- ( ( S e. Word B /\ T e. Word B ) -> T : ( 0 ..^ ( # ` T ) ) --> ran ( S ++ T ) ) |
| 105 | 104 | frnd | |- ( ( S e. Word B /\ T e. Word B ) -> ran T C_ ran ( S ++ T ) ) |
| 106 | 72 105 | unssd | |- ( ( S e. Word B /\ T e. Word B ) -> ( ran S u. ran T ) C_ ran ( S ++ T ) ) |
| 107 | 62 106 | eqssd | |- ( ( S e. Word B /\ T e. Word B ) -> ran ( S ++ T ) = ( ran S u. ran T ) ) |