| Step | Hyp | Ref | Expression | 
						
							| 1 |  | tfsconcat.op | ⊢  +   =  ( 𝑎  ∈  V ,  𝑏  ∈  V  ↦  ( 𝑎  ∪  { 〈 𝑥 ,  𝑦 〉  ∣  ( 𝑥  ∈  ( ( dom  𝑎  +o  dom  𝑏 )  ∖  dom  𝑎 )  ∧  ∃ 𝑧  ∈  dom  𝑏 ( 𝑥  =  ( dom  𝑎  +o  𝑧 )  ∧  𝑦  =  ( 𝑏 ‘ 𝑧 ) ) ) } ) ) | 
						
							| 2 |  | dffn3 | ⊢ ( 𝐹  Fn  ( 𝐶  +o  𝐷 )  ↔  𝐹 : ( 𝐶  +o  𝐷 ) ⟶ ran  𝐹 ) | 
						
							| 3 | 2 | biimpi | ⊢ ( 𝐹  Fn  ( 𝐶  +o  𝐷 )  →  𝐹 : ( 𝐶  +o  𝐷 ) ⟶ ran  𝐹 ) | 
						
							| 4 | 3 | adantr | ⊢ ( ( 𝐹  Fn  ( 𝐶  +o  𝐷 )  ∧  ( 𝐶  ∈  On  ∧  𝐷  ∈  On ) )  →  𝐹 : ( 𝐶  +o  𝐷 ) ⟶ ran  𝐹 ) | 
						
							| 5 |  | fndm | ⊢ ( 𝐹  Fn  ( 𝐶  +o  𝐷 )  →  dom  𝐹  =  ( 𝐶  +o  𝐷 ) ) | 
						
							| 6 | 5 | adantr | ⊢ ( ( 𝐹  Fn  ( 𝐶  +o  𝐷 )  ∧  ( 𝐶  ∈  On  ∧  𝐷  ∈  On ) )  →  dom  𝐹  =  ( 𝐶  +o  𝐷 ) ) | 
						
							| 7 |  | oacl | ⊢ ( ( 𝐶  ∈  On  ∧  𝐷  ∈  On )  →  ( 𝐶  +o  𝐷 )  ∈  On ) | 
						
							| 8 | 7 | adantl | ⊢ ( ( 𝐹  Fn  ( 𝐶  +o  𝐷 )  ∧  ( 𝐶  ∈  On  ∧  𝐷  ∈  On ) )  →  ( 𝐶  +o  𝐷 )  ∈  On ) | 
						
							| 9 | 6 8 | eqeltrd | ⊢ ( ( 𝐹  Fn  ( 𝐶  +o  𝐷 )  ∧  ( 𝐶  ∈  On  ∧  𝐷  ∈  On ) )  →  dom  𝐹  ∈  On ) | 
						
							| 10 |  | fnfun | ⊢ ( 𝐹  Fn  ( 𝐶  +o  𝐷 )  →  Fun  𝐹 ) | 
						
							| 11 | 10 | adantr | ⊢ ( ( 𝐹  Fn  ( 𝐶  +o  𝐷 )  ∧  ( 𝐶  ∈  On  ∧  𝐷  ∈  On ) )  →  Fun  𝐹 ) | 
						
							| 12 |  | funrnex | ⊢ ( dom  𝐹  ∈  On  →  ( Fun  𝐹  →  ran  𝐹  ∈  V ) ) | 
						
							| 13 | 9 11 12 | sylc | ⊢ ( ( 𝐹  Fn  ( 𝐶  +o  𝐷 )  ∧  ( 𝐶  ∈  On  ∧  𝐷  ∈  On ) )  →  ran  𝐹  ∈  V ) | 
						
							| 14 | 13 8 | elmapd | ⊢ ( ( 𝐹  Fn  ( 𝐶  +o  𝐷 )  ∧  ( 𝐶  ∈  On  ∧  𝐷  ∈  On ) )  →  ( 𝐹  ∈  ( ran  𝐹  ↑m  ( 𝐶  +o  𝐷 ) )  ↔  𝐹 : ( 𝐶  +o  𝐷 ) ⟶ ran  𝐹 ) ) | 
						
							| 15 | 4 14 | mpbird | ⊢ ( ( 𝐹  Fn  ( 𝐶  +o  𝐷 )  ∧  ( 𝐶  ∈  On  ∧  𝐷  ∈  On ) )  →  𝐹  ∈  ( ran  𝐹  ↑m  ( 𝐶  +o  𝐷 ) ) ) | 
						
							| 16 |  | oaword1 | ⊢ ( ( 𝐶  ∈  On  ∧  𝐷  ∈  On )  →  𝐶  ⊆  ( 𝐶  +o  𝐷 ) ) | 
						
							| 17 | 16 | adantl | ⊢ ( ( 𝐹  Fn  ( 𝐶  +o  𝐷 )  ∧  ( 𝐶  ∈  On  ∧  𝐷  ∈  On ) )  →  𝐶  ⊆  ( 𝐶  +o  𝐷 ) ) | 
						
							| 18 |  | elmapssres | ⊢ ( ( 𝐹  ∈  ( ran  𝐹  ↑m  ( 𝐶  +o  𝐷 ) )  ∧  𝐶  ⊆  ( 𝐶  +o  𝐷 ) )  →  ( 𝐹  ↾  𝐶 )  ∈  ( ran  𝐹  ↑m  𝐶 ) ) | 
						
							| 19 | 15 17 18 | syl2anc | ⊢ ( ( 𝐹  Fn  ( 𝐶  +o  𝐷 )  ∧  ( 𝐶  ∈  On  ∧  𝐷  ∈  On ) )  →  ( 𝐹  ↾  𝐶 )  ∈  ( ran  𝐹  ↑m  𝐶 ) ) | 
						
							| 20 |  | simpl | ⊢ ( ( 𝐹  Fn  ( 𝐶  +o  𝐷 )  ∧  ( 𝐶  ∈  On  ∧  𝐷  ∈  On ) )  →  𝐹  Fn  ( 𝐶  +o  𝐷 ) ) | 
						
							| 21 |  | oaordi | ⊢ ( ( 𝐷  ∈  On  ∧  𝐶  ∈  On )  →  ( 𝑑  ∈  𝐷  →  ( 𝐶  +o  𝑑 )  ∈  ( 𝐶  +o  𝐷 ) ) ) | 
						
							| 22 | 21 | ancoms | ⊢ ( ( 𝐶  ∈  On  ∧  𝐷  ∈  On )  →  ( 𝑑  ∈  𝐷  →  ( 𝐶  +o  𝑑 )  ∈  ( 𝐶  +o  𝐷 ) ) ) | 
						
							| 23 | 22 | adantl | ⊢ ( ( 𝐹  Fn  ( 𝐶  +o  𝐷 )  ∧  ( 𝐶  ∈  On  ∧  𝐷  ∈  On ) )  →  ( 𝑑  ∈  𝐷  →  ( 𝐶  +o  𝑑 )  ∈  ( 𝐶  +o  𝐷 ) ) ) | 
						
							| 24 | 23 | imp | ⊢ ( ( ( 𝐹  Fn  ( 𝐶  +o  𝐷 )  ∧  ( 𝐶  ∈  On  ∧  𝐷  ∈  On ) )  ∧  𝑑  ∈  𝐷 )  →  ( 𝐶  +o  𝑑 )  ∈  ( 𝐶  +o  𝐷 ) ) | 
						
							| 25 |  | fnfvelrn | ⊢ ( ( 𝐹  Fn  ( 𝐶  +o  𝐷 )  ∧  ( 𝐶  +o  𝑑 )  ∈  ( 𝐶  +o  𝐷 ) )  →  ( 𝐹 ‘ ( 𝐶  +o  𝑑 ) )  ∈  ran  𝐹 ) | 
						
							| 26 | 20 24 25 | syl2an2r | ⊢ ( ( ( 𝐹  Fn  ( 𝐶  +o  𝐷 )  ∧  ( 𝐶  ∈  On  ∧  𝐷  ∈  On ) )  ∧  𝑑  ∈  𝐷 )  →  ( 𝐹 ‘ ( 𝐶  +o  𝑑 ) )  ∈  ran  𝐹 ) | 
						
							| 27 | 26 | fmpttd | ⊢ ( ( 𝐹  Fn  ( 𝐶  +o  𝐷 )  ∧  ( 𝐶  ∈  On  ∧  𝐷  ∈  On ) )  →  ( 𝑑  ∈  𝐷  ↦  ( 𝐹 ‘ ( 𝐶  +o  𝑑 ) ) ) : 𝐷 ⟶ ran  𝐹 ) | 
						
							| 28 |  | simprr | ⊢ ( ( 𝐹  Fn  ( 𝐶  +o  𝐷 )  ∧  ( 𝐶  ∈  On  ∧  𝐷  ∈  On ) )  →  𝐷  ∈  On ) | 
						
							| 29 | 13 28 | elmapd | ⊢ ( ( 𝐹  Fn  ( 𝐶  +o  𝐷 )  ∧  ( 𝐶  ∈  On  ∧  𝐷  ∈  On ) )  →  ( ( 𝑑  ∈  𝐷  ↦  ( 𝐹 ‘ ( 𝐶  +o  𝑑 ) ) )  ∈  ( ran  𝐹  ↑m  𝐷 )  ↔  ( 𝑑  ∈  𝐷  ↦  ( 𝐹 ‘ ( 𝐶  +o  𝑑 ) ) ) : 𝐷 ⟶ ran  𝐹 ) ) | 
						
							| 30 | 27 29 | mpbird | ⊢ ( ( 𝐹  Fn  ( 𝐶  +o  𝐷 )  ∧  ( 𝐶  ∈  On  ∧  𝐷  ∈  On ) )  →  ( 𝑑  ∈  𝐷  ↦  ( 𝐹 ‘ ( 𝐶  +o  𝑑 ) ) )  ∈  ( ran  𝐹  ↑m  𝐷 ) ) | 
						
							| 31 | 20 17 | fnssresd | ⊢ ( ( 𝐹  Fn  ( 𝐶  +o  𝐷 )  ∧  ( 𝐶  ∈  On  ∧  𝐷  ∈  On ) )  →  ( 𝐹  ↾  𝐶 )  Fn  𝐶 ) | 
						
							| 32 |  | fvex | ⊢ ( 𝐹 ‘ ( 𝐶  +o  𝑑 ) )  ∈  V | 
						
							| 33 |  | eqid | ⊢ ( 𝑑  ∈  𝐷  ↦  ( 𝐹 ‘ ( 𝐶  +o  𝑑 ) ) )  =  ( 𝑑  ∈  𝐷  ↦  ( 𝐹 ‘ ( 𝐶  +o  𝑑 ) ) ) | 
						
							| 34 | 32 33 | fnmpti | ⊢ ( 𝑑  ∈  𝐷  ↦  ( 𝐹 ‘ ( 𝐶  +o  𝑑 ) ) )  Fn  𝐷 | 
						
							| 35 | 34 | a1i | ⊢ ( ( 𝐹  Fn  ( 𝐶  +o  𝐷 )  ∧  ( 𝐶  ∈  On  ∧  𝐷  ∈  On ) )  →  ( 𝑑  ∈  𝐷  ↦  ( 𝐹 ‘ ( 𝐶  +o  𝑑 ) ) )  Fn  𝐷 ) | 
						
							| 36 |  | simpr | ⊢ ( ( 𝐹  Fn  ( 𝐶  +o  𝐷 )  ∧  ( 𝐶  ∈  On  ∧  𝐷  ∈  On ) )  →  ( 𝐶  ∈  On  ∧  𝐷  ∈  On ) ) | 
						
							| 37 | 1 | tfsconcatun | ⊢ ( ( ( ( 𝐹  ↾  𝐶 )  Fn  𝐶  ∧  ( 𝑑  ∈  𝐷  ↦  ( 𝐹 ‘ ( 𝐶  +o  𝑑 ) ) )  Fn  𝐷 )  ∧  ( 𝐶  ∈  On  ∧  𝐷  ∈  On ) )  →  ( ( 𝐹  ↾  𝐶 )  +  ( 𝑑  ∈  𝐷  ↦  ( 𝐹 ‘ ( 𝐶  +o  𝑑 ) ) ) )  =  ( ( 𝐹  ↾  𝐶 )  ∪  { 〈 𝑥 ,  𝑦 〉  ∣  ( 𝑥  ∈  ( ( 𝐶  +o  𝐷 )  ∖  𝐶 )  ∧  ∃ 𝑧  ∈  𝐷 ( 𝑥  =  ( 𝐶  +o  𝑧 )  ∧  𝑦  =  ( ( 𝑑  ∈  𝐷  ↦  ( 𝐹 ‘ ( 𝐶  +o  𝑑 ) ) ) ‘ 𝑧 ) ) ) } ) ) | 
						
							| 38 | 31 35 36 37 | syl21anc | ⊢ ( ( 𝐹  Fn  ( 𝐶  +o  𝐷 )  ∧  ( 𝐶  ∈  On  ∧  𝐷  ∈  On ) )  →  ( ( 𝐹  ↾  𝐶 )  +  ( 𝑑  ∈  𝐷  ↦  ( 𝐹 ‘ ( 𝐶  +o  𝑑 ) ) ) )  =  ( ( 𝐹  ↾  𝐶 )  ∪  { 〈 𝑥 ,  𝑦 〉  ∣  ( 𝑥  ∈  ( ( 𝐶  +o  𝐷 )  ∖  𝐶 )  ∧  ∃ 𝑧  ∈  𝐷 ( 𝑥  =  ( 𝐶  +o  𝑧 )  ∧  𝑦  =  ( ( 𝑑  ∈  𝐷  ↦  ( 𝐹 ‘ ( 𝐶  +o  𝑑 ) ) ) ‘ 𝑧 ) ) ) } ) ) | 
						
							| 39 |  | oveq2 | ⊢ ( 𝑑  =  𝑧  →  ( 𝐶  +o  𝑑 )  =  ( 𝐶  +o  𝑧 ) ) | 
						
							| 40 | 39 | fveq2d | ⊢ ( 𝑑  =  𝑧  →  ( 𝐹 ‘ ( 𝐶  +o  𝑑 ) )  =  ( 𝐹 ‘ ( 𝐶  +o  𝑧 ) ) ) | 
						
							| 41 |  | fvex | ⊢ ( 𝐹 ‘ ( 𝐶  +o  𝑧 ) )  ∈  V | 
						
							| 42 | 40 33 41 | fvmpt | ⊢ ( 𝑧  ∈  𝐷  →  ( ( 𝑑  ∈  𝐷  ↦  ( 𝐹 ‘ ( 𝐶  +o  𝑑 ) ) ) ‘ 𝑧 )  =  ( 𝐹 ‘ ( 𝐶  +o  𝑧 ) ) ) | 
						
							| 43 | 42 | ad2antlr | ⊢ ( ( ( ( ( 𝐹  Fn  ( 𝐶  +o  𝐷 )  ∧  ( 𝐶  ∈  On  ∧  𝐷  ∈  On ) )  ∧  𝑥  ∈  ( ( 𝐶  +o  𝐷 )  ∖  𝐶 ) )  ∧  𝑧  ∈  𝐷 )  ∧  𝑥  =  ( 𝐶  +o  𝑧 ) )  →  ( ( 𝑑  ∈  𝐷  ↦  ( 𝐹 ‘ ( 𝐶  +o  𝑑 ) ) ) ‘ 𝑧 )  =  ( 𝐹 ‘ ( 𝐶  +o  𝑧 ) ) ) | 
						
							| 44 |  | fveq2 | ⊢ ( 𝑥  =  ( 𝐶  +o  𝑧 )  →  ( 𝐹 ‘ 𝑥 )  =  ( 𝐹 ‘ ( 𝐶  +o  𝑧 ) ) ) | 
						
							| 45 | 44 | adantl | ⊢ ( ( ( ( ( 𝐹  Fn  ( 𝐶  +o  𝐷 )  ∧  ( 𝐶  ∈  On  ∧  𝐷  ∈  On ) )  ∧  𝑥  ∈  ( ( 𝐶  +o  𝐷 )  ∖  𝐶 ) )  ∧  𝑧  ∈  𝐷 )  ∧  𝑥  =  ( 𝐶  +o  𝑧 ) )  →  ( 𝐹 ‘ 𝑥 )  =  ( 𝐹 ‘ ( 𝐶  +o  𝑧 ) ) ) | 
						
							| 46 | 43 45 | eqtr4d | ⊢ ( ( ( ( ( 𝐹  Fn  ( 𝐶  +o  𝐷 )  ∧  ( 𝐶  ∈  On  ∧  𝐷  ∈  On ) )  ∧  𝑥  ∈  ( ( 𝐶  +o  𝐷 )  ∖  𝐶 ) )  ∧  𝑧  ∈  𝐷 )  ∧  𝑥  =  ( 𝐶  +o  𝑧 ) )  →  ( ( 𝑑  ∈  𝐷  ↦  ( 𝐹 ‘ ( 𝐶  +o  𝑑 ) ) ) ‘ 𝑧 )  =  ( 𝐹 ‘ 𝑥 ) ) | 
						
							| 47 | 46 | eqeq2d | ⊢ ( ( ( ( ( 𝐹  Fn  ( 𝐶  +o  𝐷 )  ∧  ( 𝐶  ∈  On  ∧  𝐷  ∈  On ) )  ∧  𝑥  ∈  ( ( 𝐶  +o  𝐷 )  ∖  𝐶 ) )  ∧  𝑧  ∈  𝐷 )  ∧  𝑥  =  ( 𝐶  +o  𝑧 ) )  →  ( 𝑦  =  ( ( 𝑑  ∈  𝐷  ↦  ( 𝐹 ‘ ( 𝐶  +o  𝑑 ) ) ) ‘ 𝑧 )  ↔  𝑦  =  ( 𝐹 ‘ 𝑥 ) ) ) | 
						
							| 48 | 47 | biimpd | ⊢ ( ( ( ( ( 𝐹  Fn  ( 𝐶  +o  𝐷 )  ∧  ( 𝐶  ∈  On  ∧  𝐷  ∈  On ) )  ∧  𝑥  ∈  ( ( 𝐶  +o  𝐷 )  ∖  𝐶 ) )  ∧  𝑧  ∈  𝐷 )  ∧  𝑥  =  ( 𝐶  +o  𝑧 ) )  →  ( 𝑦  =  ( ( 𝑑  ∈  𝐷  ↦  ( 𝐹 ‘ ( 𝐶  +o  𝑑 ) ) ) ‘ 𝑧 )  →  𝑦  =  ( 𝐹 ‘ 𝑥 ) ) ) | 
						
							| 49 | 48 | expimpd | ⊢ ( ( ( ( 𝐹  Fn  ( 𝐶  +o  𝐷 )  ∧  ( 𝐶  ∈  On  ∧  𝐷  ∈  On ) )  ∧  𝑥  ∈  ( ( 𝐶  +o  𝐷 )  ∖  𝐶 ) )  ∧  𝑧  ∈  𝐷 )  →  ( ( 𝑥  =  ( 𝐶  +o  𝑧 )  ∧  𝑦  =  ( ( 𝑑  ∈  𝐷  ↦  ( 𝐹 ‘ ( 𝐶  +o  𝑑 ) ) ) ‘ 𝑧 ) )  →  𝑦  =  ( 𝐹 ‘ 𝑥 ) ) ) | 
						
							| 50 | 49 | rexlimdva | ⊢ ( ( ( 𝐹  Fn  ( 𝐶  +o  𝐷 )  ∧  ( 𝐶  ∈  On  ∧  𝐷  ∈  On ) )  ∧  𝑥  ∈  ( ( 𝐶  +o  𝐷 )  ∖  𝐶 ) )  →  ( ∃ 𝑧  ∈  𝐷 ( 𝑥  =  ( 𝐶  +o  𝑧 )  ∧  𝑦  =  ( ( 𝑑  ∈  𝐷  ↦  ( 𝐹 ‘ ( 𝐶  +o  𝑑 ) ) ) ‘ 𝑧 ) )  →  𝑦  =  ( 𝐹 ‘ 𝑥 ) ) ) | 
						
							| 51 |  | simplr | ⊢ ( ( ( 𝐹  Fn  ( 𝐶  +o  𝐷 )  ∧  ( 𝐶  ∈  On  ∧  𝐷  ∈  On ) )  ∧  𝑥  ∈  ( ( 𝐶  +o  𝐷 )  ∖  𝐶 ) )  →  ( 𝐶  ∈  On  ∧  𝐷  ∈  On ) ) | 
						
							| 52 |  | eloni | ⊢ ( ( 𝐶  +o  𝐷 )  ∈  On  →  Ord  ( 𝐶  +o  𝐷 ) ) | 
						
							| 53 | 7 52 | syl | ⊢ ( ( 𝐶  ∈  On  ∧  𝐷  ∈  On )  →  Ord  ( 𝐶  +o  𝐷 ) ) | 
						
							| 54 |  | eloni | ⊢ ( 𝐶  ∈  On  →  Ord  𝐶 ) | 
						
							| 55 | 54 | adantr | ⊢ ( ( 𝐶  ∈  On  ∧  𝐷  ∈  On )  →  Ord  𝐶 ) | 
						
							| 56 |  | ordeldif | ⊢ ( ( Ord  ( 𝐶  +o  𝐷 )  ∧  Ord  𝐶 )  →  ( 𝑥  ∈  ( ( 𝐶  +o  𝐷 )  ∖  𝐶 )  ↔  ( 𝑥  ∈  ( 𝐶  +o  𝐷 )  ∧  𝐶  ⊆  𝑥 ) ) ) | 
						
							| 57 | 53 55 56 | syl2anc | ⊢ ( ( 𝐶  ∈  On  ∧  𝐷  ∈  On )  →  ( 𝑥  ∈  ( ( 𝐶  +o  𝐷 )  ∖  𝐶 )  ↔  ( 𝑥  ∈  ( 𝐶  +o  𝐷 )  ∧  𝐶  ⊆  𝑥 ) ) ) | 
						
							| 58 | 57 | adantl | ⊢ ( ( 𝐹  Fn  ( 𝐶  +o  𝐷 )  ∧  ( 𝐶  ∈  On  ∧  𝐷  ∈  On ) )  →  ( 𝑥  ∈  ( ( 𝐶  +o  𝐷 )  ∖  𝐶 )  ↔  ( 𝑥  ∈  ( 𝐶  +o  𝐷 )  ∧  𝐶  ⊆  𝑥 ) ) ) | 
						
							| 59 | 58 | biimpa | ⊢ ( ( ( 𝐹  Fn  ( 𝐶  +o  𝐷 )  ∧  ( 𝐶  ∈  On  ∧  𝐷  ∈  On ) )  ∧  𝑥  ∈  ( ( 𝐶  +o  𝐷 )  ∖  𝐶 ) )  →  ( 𝑥  ∈  ( 𝐶  +o  𝐷 )  ∧  𝐶  ⊆  𝑥 ) ) | 
						
							| 60 | 59 | ancomd | ⊢ ( ( ( 𝐹  Fn  ( 𝐶  +o  𝐷 )  ∧  ( 𝐶  ∈  On  ∧  𝐷  ∈  On ) )  ∧  𝑥  ∈  ( ( 𝐶  +o  𝐷 )  ∖  𝐶 ) )  →  ( 𝐶  ⊆  𝑥  ∧  𝑥  ∈  ( 𝐶  +o  𝐷 ) ) ) | 
						
							| 61 | 51 60 | jca | ⊢ ( ( ( 𝐹  Fn  ( 𝐶  +o  𝐷 )  ∧  ( 𝐶  ∈  On  ∧  𝐷  ∈  On ) )  ∧  𝑥  ∈  ( ( 𝐶  +o  𝐷 )  ∖  𝐶 ) )  →  ( ( 𝐶  ∈  On  ∧  𝐷  ∈  On )  ∧  ( 𝐶  ⊆  𝑥  ∧  𝑥  ∈  ( 𝐶  +o  𝐷 ) ) ) ) | 
						
							| 62 | 61 | adantr | ⊢ ( ( ( ( 𝐹  Fn  ( 𝐶  +o  𝐷 )  ∧  ( 𝐶  ∈  On  ∧  𝐷  ∈  On ) )  ∧  𝑥  ∈  ( ( 𝐶  +o  𝐷 )  ∖  𝐶 ) )  ∧  𝑦  =  ( 𝐹 ‘ 𝑥 ) )  →  ( ( 𝐶  ∈  On  ∧  𝐷  ∈  On )  ∧  ( 𝐶  ⊆  𝑥  ∧  𝑥  ∈  ( 𝐶  +o  𝐷 ) ) ) ) | 
						
							| 63 |  | oawordex2 | ⊢ ( ( ( 𝐶  ∈  On  ∧  𝐷  ∈  On )  ∧  ( 𝐶  ⊆  𝑥  ∧  𝑥  ∈  ( 𝐶  +o  𝐷 ) ) )  →  ∃ 𝑧  ∈  𝐷 ( 𝐶  +o  𝑧 )  =  𝑥 ) | 
						
							| 64 | 62 63 | syl | ⊢ ( ( ( ( 𝐹  Fn  ( 𝐶  +o  𝐷 )  ∧  ( 𝐶  ∈  On  ∧  𝐷  ∈  On ) )  ∧  𝑥  ∈  ( ( 𝐶  +o  𝐷 )  ∖  𝐶 ) )  ∧  𝑦  =  ( 𝐹 ‘ 𝑥 ) )  →  ∃ 𝑧  ∈  𝐷 ( 𝐶  +o  𝑧 )  =  𝑥 ) | 
						
							| 65 |  | simpr | ⊢ ( ( ( ( ( ( 𝐹  Fn  ( 𝐶  +o  𝐷 )  ∧  ( 𝐶  ∈  On  ∧  𝐷  ∈  On ) )  ∧  𝑥  ∈  ( ( 𝐶  +o  𝐷 )  ∖  𝐶 ) )  ∧  𝑦  =  ( 𝐹 ‘ 𝑥 ) )  ∧  𝑧  ∈  𝐷 )  ∧  ( 𝐶  +o  𝑧 )  =  𝑥 )  →  ( 𝐶  +o  𝑧 )  =  𝑥 ) | 
						
							| 66 | 65 | eqcomd | ⊢ ( ( ( ( ( ( 𝐹  Fn  ( 𝐶  +o  𝐷 )  ∧  ( 𝐶  ∈  On  ∧  𝐷  ∈  On ) )  ∧  𝑥  ∈  ( ( 𝐶  +o  𝐷 )  ∖  𝐶 ) )  ∧  𝑦  =  ( 𝐹 ‘ 𝑥 ) )  ∧  𝑧  ∈  𝐷 )  ∧  ( 𝐶  +o  𝑧 )  =  𝑥 )  →  𝑥  =  ( 𝐶  +o  𝑧 ) ) | 
						
							| 67 | 65 | fveq2d | ⊢ ( ( ( ( ( ( 𝐹  Fn  ( 𝐶  +o  𝐷 )  ∧  ( 𝐶  ∈  On  ∧  𝐷  ∈  On ) )  ∧  𝑥  ∈  ( ( 𝐶  +o  𝐷 )  ∖  𝐶 ) )  ∧  𝑦  =  ( 𝐹 ‘ 𝑥 ) )  ∧  𝑧  ∈  𝐷 )  ∧  ( 𝐶  +o  𝑧 )  =  𝑥 )  →  ( 𝐹 ‘ ( 𝐶  +o  𝑧 ) )  =  ( 𝐹 ‘ 𝑥 ) ) | 
						
							| 68 | 42 | ad2antlr | ⊢ ( ( ( ( ( ( 𝐹  Fn  ( 𝐶  +o  𝐷 )  ∧  ( 𝐶  ∈  On  ∧  𝐷  ∈  On ) )  ∧  𝑥  ∈  ( ( 𝐶  +o  𝐷 )  ∖  𝐶 ) )  ∧  𝑦  =  ( 𝐹 ‘ 𝑥 ) )  ∧  𝑧  ∈  𝐷 )  ∧  ( 𝐶  +o  𝑧 )  =  𝑥 )  →  ( ( 𝑑  ∈  𝐷  ↦  ( 𝐹 ‘ ( 𝐶  +o  𝑑 ) ) ) ‘ 𝑧 )  =  ( 𝐹 ‘ ( 𝐶  +o  𝑧 ) ) ) | 
						
							| 69 |  | simpllr | ⊢ ( ( ( ( ( ( 𝐹  Fn  ( 𝐶  +o  𝐷 )  ∧  ( 𝐶  ∈  On  ∧  𝐷  ∈  On ) )  ∧  𝑥  ∈  ( ( 𝐶  +o  𝐷 )  ∖  𝐶 ) )  ∧  𝑦  =  ( 𝐹 ‘ 𝑥 ) )  ∧  𝑧  ∈  𝐷 )  ∧  ( 𝐶  +o  𝑧 )  =  𝑥 )  →  𝑦  =  ( 𝐹 ‘ 𝑥 ) ) | 
						
							| 70 | 67 68 69 | 3eqtr4rd | ⊢ ( ( ( ( ( ( 𝐹  Fn  ( 𝐶  +o  𝐷 )  ∧  ( 𝐶  ∈  On  ∧  𝐷  ∈  On ) )  ∧  𝑥  ∈  ( ( 𝐶  +o  𝐷 )  ∖  𝐶 ) )  ∧  𝑦  =  ( 𝐹 ‘ 𝑥 ) )  ∧  𝑧  ∈  𝐷 )  ∧  ( 𝐶  +o  𝑧 )  =  𝑥 )  →  𝑦  =  ( ( 𝑑  ∈  𝐷  ↦  ( 𝐹 ‘ ( 𝐶  +o  𝑑 ) ) ) ‘ 𝑧 ) ) | 
						
							| 71 | 66 70 | jca | ⊢ ( ( ( ( ( ( 𝐹  Fn  ( 𝐶  +o  𝐷 )  ∧  ( 𝐶  ∈  On  ∧  𝐷  ∈  On ) )  ∧  𝑥  ∈  ( ( 𝐶  +o  𝐷 )  ∖  𝐶 ) )  ∧  𝑦  =  ( 𝐹 ‘ 𝑥 ) )  ∧  𝑧  ∈  𝐷 )  ∧  ( 𝐶  +o  𝑧 )  =  𝑥 )  →  ( 𝑥  =  ( 𝐶  +o  𝑧 )  ∧  𝑦  =  ( ( 𝑑  ∈  𝐷  ↦  ( 𝐹 ‘ ( 𝐶  +o  𝑑 ) ) ) ‘ 𝑧 ) ) ) | 
						
							| 72 | 71 | ex | ⊢ ( ( ( ( ( 𝐹  Fn  ( 𝐶  +o  𝐷 )  ∧  ( 𝐶  ∈  On  ∧  𝐷  ∈  On ) )  ∧  𝑥  ∈  ( ( 𝐶  +o  𝐷 )  ∖  𝐶 ) )  ∧  𝑦  =  ( 𝐹 ‘ 𝑥 ) )  ∧  𝑧  ∈  𝐷 )  →  ( ( 𝐶  +o  𝑧 )  =  𝑥  →  ( 𝑥  =  ( 𝐶  +o  𝑧 )  ∧  𝑦  =  ( ( 𝑑  ∈  𝐷  ↦  ( 𝐹 ‘ ( 𝐶  +o  𝑑 ) ) ) ‘ 𝑧 ) ) ) ) | 
						
							| 73 | 72 | reximdva | ⊢ ( ( ( ( 𝐹  Fn  ( 𝐶  +o  𝐷 )  ∧  ( 𝐶  ∈  On  ∧  𝐷  ∈  On ) )  ∧  𝑥  ∈  ( ( 𝐶  +o  𝐷 )  ∖  𝐶 ) )  ∧  𝑦  =  ( 𝐹 ‘ 𝑥 ) )  →  ( ∃ 𝑧  ∈  𝐷 ( 𝐶  +o  𝑧 )  =  𝑥  →  ∃ 𝑧  ∈  𝐷 ( 𝑥  =  ( 𝐶  +o  𝑧 )  ∧  𝑦  =  ( ( 𝑑  ∈  𝐷  ↦  ( 𝐹 ‘ ( 𝐶  +o  𝑑 ) ) ) ‘ 𝑧 ) ) ) ) | 
						
							| 74 | 64 73 | mpd | ⊢ ( ( ( ( 𝐹  Fn  ( 𝐶  +o  𝐷 )  ∧  ( 𝐶  ∈  On  ∧  𝐷  ∈  On ) )  ∧  𝑥  ∈  ( ( 𝐶  +o  𝐷 )  ∖  𝐶 ) )  ∧  𝑦  =  ( 𝐹 ‘ 𝑥 ) )  →  ∃ 𝑧  ∈  𝐷 ( 𝑥  =  ( 𝐶  +o  𝑧 )  ∧  𝑦  =  ( ( 𝑑  ∈  𝐷  ↦  ( 𝐹 ‘ ( 𝐶  +o  𝑑 ) ) ) ‘ 𝑧 ) ) ) | 
						
							| 75 | 74 | ex | ⊢ ( ( ( 𝐹  Fn  ( 𝐶  +o  𝐷 )  ∧  ( 𝐶  ∈  On  ∧  𝐷  ∈  On ) )  ∧  𝑥  ∈  ( ( 𝐶  +o  𝐷 )  ∖  𝐶 ) )  →  ( 𝑦  =  ( 𝐹 ‘ 𝑥 )  →  ∃ 𝑧  ∈  𝐷 ( 𝑥  =  ( 𝐶  +o  𝑧 )  ∧  𝑦  =  ( ( 𝑑  ∈  𝐷  ↦  ( 𝐹 ‘ ( 𝐶  +o  𝑑 ) ) ) ‘ 𝑧 ) ) ) ) | 
						
							| 76 | 50 75 | impbid | ⊢ ( ( ( 𝐹  Fn  ( 𝐶  +o  𝐷 )  ∧  ( 𝐶  ∈  On  ∧  𝐷  ∈  On ) )  ∧  𝑥  ∈  ( ( 𝐶  +o  𝐷 )  ∖  𝐶 ) )  →  ( ∃ 𝑧  ∈  𝐷 ( 𝑥  =  ( 𝐶  +o  𝑧 )  ∧  𝑦  =  ( ( 𝑑  ∈  𝐷  ↦  ( 𝐹 ‘ ( 𝐶  +o  𝑑 ) ) ) ‘ 𝑧 ) )  ↔  𝑦  =  ( 𝐹 ‘ 𝑥 ) ) ) | 
						
							| 77 |  | eldifi | ⊢ ( 𝑥  ∈  ( ( 𝐶  +o  𝐷 )  ∖  𝐶 )  →  𝑥  ∈  ( 𝐶  +o  𝐷 ) ) | 
						
							| 78 |  | eqcom | ⊢ ( 𝑦  =  ( 𝐹 ‘ 𝑥 )  ↔  ( 𝐹 ‘ 𝑥 )  =  𝑦 ) | 
						
							| 79 |  | fnbrfvb | ⊢ ( ( 𝐹  Fn  ( 𝐶  +o  𝐷 )  ∧  𝑥  ∈  ( 𝐶  +o  𝐷 ) )  →  ( ( 𝐹 ‘ 𝑥 )  =  𝑦  ↔  𝑥 𝐹 𝑦 ) ) | 
						
							| 80 | 78 79 | bitrid | ⊢ ( ( 𝐹  Fn  ( 𝐶  +o  𝐷 )  ∧  𝑥  ∈  ( 𝐶  +o  𝐷 ) )  →  ( 𝑦  =  ( 𝐹 ‘ 𝑥 )  ↔  𝑥 𝐹 𝑦 ) ) | 
						
							| 81 | 20 77 80 | syl2an | ⊢ ( ( ( 𝐹  Fn  ( 𝐶  +o  𝐷 )  ∧  ( 𝐶  ∈  On  ∧  𝐷  ∈  On ) )  ∧  𝑥  ∈  ( ( 𝐶  +o  𝐷 )  ∖  𝐶 ) )  →  ( 𝑦  =  ( 𝐹 ‘ 𝑥 )  ↔  𝑥 𝐹 𝑦 ) ) | 
						
							| 82 | 76 81 | bitrd | ⊢ ( ( ( 𝐹  Fn  ( 𝐶  +o  𝐷 )  ∧  ( 𝐶  ∈  On  ∧  𝐷  ∈  On ) )  ∧  𝑥  ∈  ( ( 𝐶  +o  𝐷 )  ∖  𝐶 ) )  →  ( ∃ 𝑧  ∈  𝐷 ( 𝑥  =  ( 𝐶  +o  𝑧 )  ∧  𝑦  =  ( ( 𝑑  ∈  𝐷  ↦  ( 𝐹 ‘ ( 𝐶  +o  𝑑 ) ) ) ‘ 𝑧 ) )  ↔  𝑥 𝐹 𝑦 ) ) | 
						
							| 83 | 82 | pm5.32da | ⊢ ( ( 𝐹  Fn  ( 𝐶  +o  𝐷 )  ∧  ( 𝐶  ∈  On  ∧  𝐷  ∈  On ) )  →  ( ( 𝑥  ∈  ( ( 𝐶  +o  𝐷 )  ∖  𝐶 )  ∧  ∃ 𝑧  ∈  𝐷 ( 𝑥  =  ( 𝐶  +o  𝑧 )  ∧  𝑦  =  ( ( 𝑑  ∈  𝐷  ↦  ( 𝐹 ‘ ( 𝐶  +o  𝑑 ) ) ) ‘ 𝑧 ) ) )  ↔  ( 𝑥  ∈  ( ( 𝐶  +o  𝐷 )  ∖  𝐶 )  ∧  𝑥 𝐹 𝑦 ) ) ) | 
						
							| 84 | 83 | opabbidv | ⊢ ( ( 𝐹  Fn  ( 𝐶  +o  𝐷 )  ∧  ( 𝐶  ∈  On  ∧  𝐷  ∈  On ) )  →  { 〈 𝑥 ,  𝑦 〉  ∣  ( 𝑥  ∈  ( ( 𝐶  +o  𝐷 )  ∖  𝐶 )  ∧  ∃ 𝑧  ∈  𝐷 ( 𝑥  =  ( 𝐶  +o  𝑧 )  ∧  𝑦  =  ( ( 𝑑  ∈  𝐷  ↦  ( 𝐹 ‘ ( 𝐶  +o  𝑑 ) ) ) ‘ 𝑧 ) ) ) }  =  { 〈 𝑥 ,  𝑦 〉  ∣  ( 𝑥  ∈  ( ( 𝐶  +o  𝐷 )  ∖  𝐶 )  ∧  𝑥 𝐹 𝑦 ) } ) | 
						
							| 85 |  | dfres2 | ⊢ ( 𝐹  ↾  ( ( 𝐶  +o  𝐷 )  ∖  𝐶 ) )  =  { 〈 𝑥 ,  𝑦 〉  ∣  ( 𝑥  ∈  ( ( 𝐶  +o  𝐷 )  ∖  𝐶 )  ∧  𝑥 𝐹 𝑦 ) } | 
						
							| 86 | 84 85 | eqtr4di | ⊢ ( ( 𝐹  Fn  ( 𝐶  +o  𝐷 )  ∧  ( 𝐶  ∈  On  ∧  𝐷  ∈  On ) )  →  { 〈 𝑥 ,  𝑦 〉  ∣  ( 𝑥  ∈  ( ( 𝐶  +o  𝐷 )  ∖  𝐶 )  ∧  ∃ 𝑧  ∈  𝐷 ( 𝑥  =  ( 𝐶  +o  𝑧 )  ∧  𝑦  =  ( ( 𝑑  ∈  𝐷  ↦  ( 𝐹 ‘ ( 𝐶  +o  𝑑 ) ) ) ‘ 𝑧 ) ) ) }  =  ( 𝐹  ↾  ( ( 𝐶  +o  𝐷 )  ∖  𝐶 ) ) ) | 
						
							| 87 | 86 | uneq2d | ⊢ ( ( 𝐹  Fn  ( 𝐶  +o  𝐷 )  ∧  ( 𝐶  ∈  On  ∧  𝐷  ∈  On ) )  →  ( ( 𝐹  ↾  𝐶 )  ∪  { 〈 𝑥 ,  𝑦 〉  ∣  ( 𝑥  ∈  ( ( 𝐶  +o  𝐷 )  ∖  𝐶 )  ∧  ∃ 𝑧  ∈  𝐷 ( 𝑥  =  ( 𝐶  +o  𝑧 )  ∧  𝑦  =  ( ( 𝑑  ∈  𝐷  ↦  ( 𝐹 ‘ ( 𝐶  +o  𝑑 ) ) ) ‘ 𝑧 ) ) ) } )  =  ( ( 𝐹  ↾  𝐶 )  ∪  ( 𝐹  ↾  ( ( 𝐶  +o  𝐷 )  ∖  𝐶 ) ) ) ) | 
						
							| 88 | 38 87 | eqtrd | ⊢ ( ( 𝐹  Fn  ( 𝐶  +o  𝐷 )  ∧  ( 𝐶  ∈  On  ∧  𝐷  ∈  On ) )  →  ( ( 𝐹  ↾  𝐶 )  +  ( 𝑑  ∈  𝐷  ↦  ( 𝐹 ‘ ( 𝐶  +o  𝑑 ) ) ) )  =  ( ( 𝐹  ↾  𝐶 )  ∪  ( 𝐹  ↾  ( ( 𝐶  +o  𝐷 )  ∖  𝐶 ) ) ) ) | 
						
							| 89 |  | resundi | ⊢ ( 𝐹  ↾  ( 𝐶  ∪  ( ( 𝐶  +o  𝐷 )  ∖  𝐶 ) ) )  =  ( ( 𝐹  ↾  𝐶 )  ∪  ( 𝐹  ↾  ( ( 𝐶  +o  𝐷 )  ∖  𝐶 ) ) ) | 
						
							| 90 | 89 | a1i | ⊢ ( ( 𝐹  Fn  ( 𝐶  +o  𝐷 )  ∧  ( 𝐶  ∈  On  ∧  𝐷  ∈  On ) )  →  ( 𝐹  ↾  ( 𝐶  ∪  ( ( 𝐶  +o  𝐷 )  ∖  𝐶 ) ) )  =  ( ( 𝐹  ↾  𝐶 )  ∪  ( 𝐹  ↾  ( ( 𝐶  +o  𝐷 )  ∖  𝐶 ) ) ) ) | 
						
							| 91 |  | undif | ⊢ ( 𝐶  ⊆  ( 𝐶  +o  𝐷 )  ↔  ( 𝐶  ∪  ( ( 𝐶  +o  𝐷 )  ∖  𝐶 ) )  =  ( 𝐶  +o  𝐷 ) ) | 
						
							| 92 | 16 91 | sylib | ⊢ ( ( 𝐶  ∈  On  ∧  𝐷  ∈  On )  →  ( 𝐶  ∪  ( ( 𝐶  +o  𝐷 )  ∖  𝐶 ) )  =  ( 𝐶  +o  𝐷 ) ) | 
						
							| 93 | 92 | adantl | ⊢ ( ( 𝐹  Fn  ( 𝐶  +o  𝐷 )  ∧  ( 𝐶  ∈  On  ∧  𝐷  ∈  On ) )  →  ( 𝐶  ∪  ( ( 𝐶  +o  𝐷 )  ∖  𝐶 ) )  =  ( 𝐶  +o  𝐷 ) ) | 
						
							| 94 | 93 | reseq2d | ⊢ ( ( 𝐹  Fn  ( 𝐶  +o  𝐷 )  ∧  ( 𝐶  ∈  On  ∧  𝐷  ∈  On ) )  →  ( 𝐹  ↾  ( 𝐶  ∪  ( ( 𝐶  +o  𝐷 )  ∖  𝐶 ) ) )  =  ( 𝐹  ↾  ( 𝐶  +o  𝐷 ) ) ) | 
						
							| 95 |  | fnresdm | ⊢ ( 𝐹  Fn  ( 𝐶  +o  𝐷 )  →  ( 𝐹  ↾  ( 𝐶  +o  𝐷 ) )  =  𝐹 ) | 
						
							| 96 | 95 | adantr | ⊢ ( ( 𝐹  Fn  ( 𝐶  +o  𝐷 )  ∧  ( 𝐶  ∈  On  ∧  𝐷  ∈  On ) )  →  ( 𝐹  ↾  ( 𝐶  +o  𝐷 ) )  =  𝐹 ) | 
						
							| 97 | 94 96 | eqtrd | ⊢ ( ( 𝐹  Fn  ( 𝐶  +o  𝐷 )  ∧  ( 𝐶  ∈  On  ∧  𝐷  ∈  On ) )  →  ( 𝐹  ↾  ( 𝐶  ∪  ( ( 𝐶  +o  𝐷 )  ∖  𝐶 ) ) )  =  𝐹 ) | 
						
							| 98 | 88 90 97 | 3eqtr2d | ⊢ ( ( 𝐹  Fn  ( 𝐶  +o  𝐷 )  ∧  ( 𝐶  ∈  On  ∧  𝐷  ∈  On ) )  →  ( ( 𝐹  ↾  𝐶 )  +  ( 𝑑  ∈  𝐷  ↦  ( 𝐹 ‘ ( 𝐶  +o  𝑑 ) ) ) )  =  𝐹 ) | 
						
							| 99 |  | dmres | ⊢ dom  ( 𝐹  ↾  𝐶 )  =  ( 𝐶  ∩  dom  𝐹 ) | 
						
							| 100 | 17 6 | sseqtrrd | ⊢ ( ( 𝐹  Fn  ( 𝐶  +o  𝐷 )  ∧  ( 𝐶  ∈  On  ∧  𝐷  ∈  On ) )  →  𝐶  ⊆  dom  𝐹 ) | 
						
							| 101 |  | dfss2 | ⊢ ( 𝐶  ⊆  dom  𝐹  ↔  ( 𝐶  ∩  dom  𝐹 )  =  𝐶 ) | 
						
							| 102 | 100 101 | sylib | ⊢ ( ( 𝐹  Fn  ( 𝐶  +o  𝐷 )  ∧  ( 𝐶  ∈  On  ∧  𝐷  ∈  On ) )  →  ( 𝐶  ∩  dom  𝐹 )  =  𝐶 ) | 
						
							| 103 | 99 102 | eqtrid | ⊢ ( ( 𝐹  Fn  ( 𝐶  +o  𝐷 )  ∧  ( 𝐶  ∈  On  ∧  𝐷  ∈  On ) )  →  dom  ( 𝐹  ↾  𝐶 )  =  𝐶 ) | 
						
							| 104 | 32 33 | dmmpti | ⊢ dom  ( 𝑑  ∈  𝐷  ↦  ( 𝐹 ‘ ( 𝐶  +o  𝑑 ) ) )  =  𝐷 | 
						
							| 105 | 104 | a1i | ⊢ ( ( 𝐹  Fn  ( 𝐶  +o  𝐷 )  ∧  ( 𝐶  ∈  On  ∧  𝐷  ∈  On ) )  →  dom  ( 𝑑  ∈  𝐷  ↦  ( 𝐹 ‘ ( 𝐶  +o  𝑑 ) ) )  =  𝐷 ) | 
						
							| 106 |  | oveq1 | ⊢ ( 𝑢  =  ( 𝐹  ↾  𝐶 )  →  ( 𝑢  +  𝑣 )  =  ( ( 𝐹  ↾  𝐶 )  +  𝑣 ) ) | 
						
							| 107 | 106 | eqeq1d | ⊢ ( 𝑢  =  ( 𝐹  ↾  𝐶 )  →  ( ( 𝑢  +  𝑣 )  =  𝐹  ↔  ( ( 𝐹  ↾  𝐶 )  +  𝑣 )  =  𝐹 ) ) | 
						
							| 108 |  | dmeq | ⊢ ( 𝑢  =  ( 𝐹  ↾  𝐶 )  →  dom  𝑢  =  dom  ( 𝐹  ↾  𝐶 ) ) | 
						
							| 109 | 108 | eqeq1d | ⊢ ( 𝑢  =  ( 𝐹  ↾  𝐶 )  →  ( dom  𝑢  =  𝐶  ↔  dom  ( 𝐹  ↾  𝐶 )  =  𝐶 ) ) | 
						
							| 110 | 107 109 | 3anbi12d | ⊢ ( 𝑢  =  ( 𝐹  ↾  𝐶 )  →  ( ( ( 𝑢  +  𝑣 )  =  𝐹  ∧  dom  𝑢  =  𝐶  ∧  dom  𝑣  =  𝐷 )  ↔  ( ( ( 𝐹  ↾  𝐶 )  +  𝑣 )  =  𝐹  ∧  dom  ( 𝐹  ↾  𝐶 )  =  𝐶  ∧  dom  𝑣  =  𝐷 ) ) ) | 
						
							| 111 |  | oveq2 | ⊢ ( 𝑣  =  ( 𝑑  ∈  𝐷  ↦  ( 𝐹 ‘ ( 𝐶  +o  𝑑 ) ) )  →  ( ( 𝐹  ↾  𝐶 )  +  𝑣 )  =  ( ( 𝐹  ↾  𝐶 )  +  ( 𝑑  ∈  𝐷  ↦  ( 𝐹 ‘ ( 𝐶  +o  𝑑 ) ) ) ) ) | 
						
							| 112 | 111 | eqeq1d | ⊢ ( 𝑣  =  ( 𝑑  ∈  𝐷  ↦  ( 𝐹 ‘ ( 𝐶  +o  𝑑 ) ) )  →  ( ( ( 𝐹  ↾  𝐶 )  +  𝑣 )  =  𝐹  ↔  ( ( 𝐹  ↾  𝐶 )  +  ( 𝑑  ∈  𝐷  ↦  ( 𝐹 ‘ ( 𝐶  +o  𝑑 ) ) ) )  =  𝐹 ) ) | 
						
							| 113 |  | dmeq | ⊢ ( 𝑣  =  ( 𝑑  ∈  𝐷  ↦  ( 𝐹 ‘ ( 𝐶  +o  𝑑 ) ) )  →  dom  𝑣  =  dom  ( 𝑑  ∈  𝐷  ↦  ( 𝐹 ‘ ( 𝐶  +o  𝑑 ) ) ) ) | 
						
							| 114 | 113 | eqeq1d | ⊢ ( 𝑣  =  ( 𝑑  ∈  𝐷  ↦  ( 𝐹 ‘ ( 𝐶  +o  𝑑 ) ) )  →  ( dom  𝑣  =  𝐷  ↔  dom  ( 𝑑  ∈  𝐷  ↦  ( 𝐹 ‘ ( 𝐶  +o  𝑑 ) ) )  =  𝐷 ) ) | 
						
							| 115 | 112 114 | 3anbi13d | ⊢ ( 𝑣  =  ( 𝑑  ∈  𝐷  ↦  ( 𝐹 ‘ ( 𝐶  +o  𝑑 ) ) )  →  ( ( ( ( 𝐹  ↾  𝐶 )  +  𝑣 )  =  𝐹  ∧  dom  ( 𝐹  ↾  𝐶 )  =  𝐶  ∧  dom  𝑣  =  𝐷 )  ↔  ( ( ( 𝐹  ↾  𝐶 )  +  ( 𝑑  ∈  𝐷  ↦  ( 𝐹 ‘ ( 𝐶  +o  𝑑 ) ) ) )  =  𝐹  ∧  dom  ( 𝐹  ↾  𝐶 )  =  𝐶  ∧  dom  ( 𝑑  ∈  𝐷  ↦  ( 𝐹 ‘ ( 𝐶  +o  𝑑 ) ) )  =  𝐷 ) ) ) | 
						
							| 116 | 110 115 | rspc2ev | ⊢ ( ( ( 𝐹  ↾  𝐶 )  ∈  ( ran  𝐹  ↑m  𝐶 )  ∧  ( 𝑑  ∈  𝐷  ↦  ( 𝐹 ‘ ( 𝐶  +o  𝑑 ) ) )  ∈  ( ran  𝐹  ↑m  𝐷 )  ∧  ( ( ( 𝐹  ↾  𝐶 )  +  ( 𝑑  ∈  𝐷  ↦  ( 𝐹 ‘ ( 𝐶  +o  𝑑 ) ) ) )  =  𝐹  ∧  dom  ( 𝐹  ↾  𝐶 )  =  𝐶  ∧  dom  ( 𝑑  ∈  𝐷  ↦  ( 𝐹 ‘ ( 𝐶  +o  𝑑 ) ) )  =  𝐷 ) )  →  ∃ 𝑢  ∈  ( ran  𝐹  ↑m  𝐶 ) ∃ 𝑣  ∈  ( ran  𝐹  ↑m  𝐷 ) ( ( 𝑢  +  𝑣 )  =  𝐹  ∧  dom  𝑢  =  𝐶  ∧  dom  𝑣  =  𝐷 ) ) | 
						
							| 117 | 19 30 98 103 105 116 | syl113anc | ⊢ ( ( 𝐹  Fn  ( 𝐶  +o  𝐷 )  ∧  ( 𝐶  ∈  On  ∧  𝐷  ∈  On ) )  →  ∃ 𝑢  ∈  ( ran  𝐹  ↑m  𝐶 ) ∃ 𝑣  ∈  ( ran  𝐹  ↑m  𝐷 ) ( ( 𝑢  +  𝑣 )  =  𝐹  ∧  dom  𝑢  =  𝐶  ∧  dom  𝑣  =  𝐷 ) ) |