| Step | Hyp | Ref | Expression | 
						
							| 1 |  | efgval.w | ⊢ 𝑊  =  (  I  ‘ Word  ( 𝐼  ×  2o ) ) | 
						
							| 2 |  | efgval.r | ⊢  ∼   =  (  ~FG  ‘ 𝐼 ) | 
						
							| 3 |  | efgval2.m | ⊢ 𝑀  =  ( 𝑦  ∈  𝐼 ,  𝑧  ∈  2o  ↦  〈 𝑦 ,  ( 1o  ∖  𝑧 ) 〉 ) | 
						
							| 4 |  | efgval2.t | ⊢ 𝑇  =  ( 𝑣  ∈  𝑊  ↦  ( 𝑛  ∈  ( 0 ... ( ♯ ‘ 𝑣 ) ) ,  𝑤  ∈  ( 𝐼  ×  2o )  ↦  ( 𝑣  splice  〈 𝑛 ,  𝑛 ,  〈“ 𝑤 ( 𝑀 ‘ 𝑤 ) ”〉 〉 ) ) ) | 
						
							| 5 |  | efgred.d | ⊢ 𝐷  =  ( 𝑊  ∖  ∪  𝑥  ∈  𝑊 ran  ( 𝑇 ‘ 𝑥 ) ) | 
						
							| 6 |  | efgred.s | ⊢ 𝑆  =  ( 𝑚  ∈  { 𝑡  ∈  ( Word  𝑊  ∖  { ∅ } )  ∣  ( ( 𝑡 ‘ 0 )  ∈  𝐷  ∧  ∀ 𝑘  ∈  ( 1 ..^ ( ♯ ‘ 𝑡 ) ) ( 𝑡 ‘ 𝑘 )  ∈  ran  ( 𝑇 ‘ ( 𝑡 ‘ ( 𝑘  −  1 ) ) ) ) }  ↦  ( 𝑚 ‘ ( ( ♯ ‘ 𝑚 )  −  1 ) ) ) | 
						
							| 7 | 1 2 3 4 5 6 | efgsf | ⊢ 𝑆 : { 𝑡  ∈  ( Word  𝑊  ∖  { ∅ } )  ∣  ( ( 𝑡 ‘ 0 )  ∈  𝐷  ∧  ∀ 𝑘  ∈  ( 1 ..^ ( ♯ ‘ 𝑡 ) ) ( 𝑡 ‘ 𝑘 )  ∈  ran  ( 𝑇 ‘ ( 𝑡 ‘ ( 𝑘  −  1 ) ) ) ) } ⟶ 𝑊 | 
						
							| 8 | 7 | fdmi | ⊢ dom  𝑆  =  { 𝑡  ∈  ( Word  𝑊  ∖  { ∅ } )  ∣  ( ( 𝑡 ‘ 0 )  ∈  𝐷  ∧  ∀ 𝑘  ∈  ( 1 ..^ ( ♯ ‘ 𝑡 ) ) ( 𝑡 ‘ 𝑘 )  ∈  ran  ( 𝑇 ‘ ( 𝑡 ‘ ( 𝑘  −  1 ) ) ) ) } | 
						
							| 9 | 8 | feq2i | ⊢ ( 𝑆 : dom  𝑆 ⟶ 𝑊  ↔  𝑆 : { 𝑡  ∈  ( Word  𝑊  ∖  { ∅ } )  ∣  ( ( 𝑡 ‘ 0 )  ∈  𝐷  ∧  ∀ 𝑘  ∈  ( 1 ..^ ( ♯ ‘ 𝑡 ) ) ( 𝑡 ‘ 𝑘 )  ∈  ran  ( 𝑇 ‘ ( 𝑡 ‘ ( 𝑘  −  1 ) ) ) ) } ⟶ 𝑊 ) | 
						
							| 10 | 7 9 | mpbir | ⊢ 𝑆 : dom  𝑆 ⟶ 𝑊 | 
						
							| 11 |  | frn | ⊢ ( 𝑆 : dom  𝑆 ⟶ 𝑊  →  ran  𝑆  ⊆  𝑊 ) | 
						
							| 12 | 10 11 | ax-mp | ⊢ ran  𝑆  ⊆  𝑊 | 
						
							| 13 |  | fviss | ⊢ (  I  ‘ Word  ( 𝐼  ×  2o ) )  ⊆  Word  ( 𝐼  ×  2o ) | 
						
							| 14 | 1 13 | eqsstri | ⊢ 𝑊  ⊆  Word  ( 𝐼  ×  2o ) | 
						
							| 15 | 14 | sseli | ⊢ ( 𝑐  ∈  𝑊  →  𝑐  ∈  Word  ( 𝐼  ×  2o ) ) | 
						
							| 16 |  | lencl | ⊢ ( 𝑐  ∈  Word  ( 𝐼  ×  2o )  →  ( ♯ ‘ 𝑐 )  ∈  ℕ0 ) | 
						
							| 17 | 15 16 | syl | ⊢ ( 𝑐  ∈  𝑊  →  ( ♯ ‘ 𝑐 )  ∈  ℕ0 ) | 
						
							| 18 |  | peano2nn0 | ⊢ ( ( ♯ ‘ 𝑐 )  ∈  ℕ0  →  ( ( ♯ ‘ 𝑐 )  +  1 )  ∈  ℕ0 ) | 
						
							| 19 | 14 | sseli | ⊢ ( 𝑎  ∈  𝑊  →  𝑎  ∈  Word  ( 𝐼  ×  2o ) ) | 
						
							| 20 |  | lencl | ⊢ ( 𝑎  ∈  Word  ( 𝐼  ×  2o )  →  ( ♯ ‘ 𝑎 )  ∈  ℕ0 ) | 
						
							| 21 | 19 20 | syl | ⊢ ( 𝑎  ∈  𝑊  →  ( ♯ ‘ 𝑎 )  ∈  ℕ0 ) | 
						
							| 22 |  | nn0nlt0 | ⊢ ( ( ♯ ‘ 𝑎 )  ∈  ℕ0  →  ¬  ( ♯ ‘ 𝑎 )  <  0 ) | 
						
							| 23 |  | breq2 | ⊢ ( 𝑏  =  0  →  ( ( ♯ ‘ 𝑎 )  <  𝑏  ↔  ( ♯ ‘ 𝑎 )  <  0 ) ) | 
						
							| 24 | 23 | notbid | ⊢ ( 𝑏  =  0  →  ( ¬  ( ♯ ‘ 𝑎 )  <  𝑏  ↔  ¬  ( ♯ ‘ 𝑎 )  <  0 ) ) | 
						
							| 25 | 22 24 | imbitrrid | ⊢ ( 𝑏  =  0  →  ( ( ♯ ‘ 𝑎 )  ∈  ℕ0  →  ¬  ( ♯ ‘ 𝑎 )  <  𝑏 ) ) | 
						
							| 26 | 21 25 | syl5 | ⊢ ( 𝑏  =  0  →  ( 𝑎  ∈  𝑊  →  ¬  ( ♯ ‘ 𝑎 )  <  𝑏 ) ) | 
						
							| 27 | 26 | ralrimiv | ⊢ ( 𝑏  =  0  →  ∀ 𝑎  ∈  𝑊 ¬  ( ♯ ‘ 𝑎 )  <  𝑏 ) | 
						
							| 28 |  | rabeq0 | ⊢ ( { 𝑎  ∈  𝑊  ∣  ( ♯ ‘ 𝑎 )  <  𝑏 }  =  ∅  ↔  ∀ 𝑎  ∈  𝑊 ¬  ( ♯ ‘ 𝑎 )  <  𝑏 ) | 
						
							| 29 | 27 28 | sylibr | ⊢ ( 𝑏  =  0  →  { 𝑎  ∈  𝑊  ∣  ( ♯ ‘ 𝑎 )  <  𝑏 }  =  ∅ ) | 
						
							| 30 | 29 | sseq1d | ⊢ ( 𝑏  =  0  →  ( { 𝑎  ∈  𝑊  ∣  ( ♯ ‘ 𝑎 )  <  𝑏 }  ⊆  ran  𝑆  ↔  ∅  ⊆  ran  𝑆 ) ) | 
						
							| 31 |  | breq2 | ⊢ ( 𝑏  =  𝑑  →  ( ( ♯ ‘ 𝑎 )  <  𝑏  ↔  ( ♯ ‘ 𝑎 )  <  𝑑 ) ) | 
						
							| 32 | 31 | rabbidv | ⊢ ( 𝑏  =  𝑑  →  { 𝑎  ∈  𝑊  ∣  ( ♯ ‘ 𝑎 )  <  𝑏 }  =  { 𝑎  ∈  𝑊  ∣  ( ♯ ‘ 𝑎 )  <  𝑑 } ) | 
						
							| 33 | 32 | sseq1d | ⊢ ( 𝑏  =  𝑑  →  ( { 𝑎  ∈  𝑊  ∣  ( ♯ ‘ 𝑎 )  <  𝑏 }  ⊆  ran  𝑆  ↔  { 𝑎  ∈  𝑊  ∣  ( ♯ ‘ 𝑎 )  <  𝑑 }  ⊆  ran  𝑆 ) ) | 
						
							| 34 |  | breq2 | ⊢ ( 𝑏  =  ( 𝑑  +  1 )  →  ( ( ♯ ‘ 𝑎 )  <  𝑏  ↔  ( ♯ ‘ 𝑎 )  <  ( 𝑑  +  1 ) ) ) | 
						
							| 35 | 34 | rabbidv | ⊢ ( 𝑏  =  ( 𝑑  +  1 )  →  { 𝑎  ∈  𝑊  ∣  ( ♯ ‘ 𝑎 )  <  𝑏 }  =  { 𝑎  ∈  𝑊  ∣  ( ♯ ‘ 𝑎 )  <  ( 𝑑  +  1 ) } ) | 
						
							| 36 | 35 | sseq1d | ⊢ ( 𝑏  =  ( 𝑑  +  1 )  →  ( { 𝑎  ∈  𝑊  ∣  ( ♯ ‘ 𝑎 )  <  𝑏 }  ⊆  ran  𝑆  ↔  { 𝑎  ∈  𝑊  ∣  ( ♯ ‘ 𝑎 )  <  ( 𝑑  +  1 ) }  ⊆  ran  𝑆 ) ) | 
						
							| 37 |  | breq2 | ⊢ ( 𝑏  =  ( ( ♯ ‘ 𝑐 )  +  1 )  →  ( ( ♯ ‘ 𝑎 )  <  𝑏  ↔  ( ♯ ‘ 𝑎 )  <  ( ( ♯ ‘ 𝑐 )  +  1 ) ) ) | 
						
							| 38 | 37 | rabbidv | ⊢ ( 𝑏  =  ( ( ♯ ‘ 𝑐 )  +  1 )  →  { 𝑎  ∈  𝑊  ∣  ( ♯ ‘ 𝑎 )  <  𝑏 }  =  { 𝑎  ∈  𝑊  ∣  ( ♯ ‘ 𝑎 )  <  ( ( ♯ ‘ 𝑐 )  +  1 ) } ) | 
						
							| 39 | 38 | sseq1d | ⊢ ( 𝑏  =  ( ( ♯ ‘ 𝑐 )  +  1 )  →  ( { 𝑎  ∈  𝑊  ∣  ( ♯ ‘ 𝑎 )  <  𝑏 }  ⊆  ran  𝑆  ↔  { 𝑎  ∈  𝑊  ∣  ( ♯ ‘ 𝑎 )  <  ( ( ♯ ‘ 𝑐 )  +  1 ) }  ⊆  ran  𝑆 ) ) | 
						
							| 40 |  | 0ss | ⊢ ∅  ⊆  ran  𝑆 | 
						
							| 41 |  | simpr | ⊢ ( ( 𝑑  ∈  ℕ0  ∧  { 𝑎  ∈  𝑊  ∣  ( ♯ ‘ 𝑎 )  <  𝑑 }  ⊆  ran  𝑆 )  →  { 𝑎  ∈  𝑊  ∣  ( ♯ ‘ 𝑎 )  <  𝑑 }  ⊆  ran  𝑆 ) | 
						
							| 42 |  | fveqeq2 | ⊢ ( 𝑎  =  𝑐  →  ( ( ♯ ‘ 𝑎 )  =  𝑑  ↔  ( ♯ ‘ 𝑐 )  =  𝑑 ) ) | 
						
							| 43 | 42 | cbvrabv | ⊢ { 𝑎  ∈  𝑊  ∣  ( ♯ ‘ 𝑎 )  =  𝑑 }  =  { 𝑐  ∈  𝑊  ∣  ( ♯ ‘ 𝑐 )  =  𝑑 } | 
						
							| 44 |  | eliun | ⊢ ( 𝑐  ∈  ∪  𝑥  ∈  𝑊 ran  ( 𝑇 ‘ 𝑥 )  ↔  ∃ 𝑥  ∈  𝑊 𝑐  ∈  ran  ( 𝑇 ‘ 𝑥 ) ) | 
						
							| 45 |  | fveq2 | ⊢ ( 𝑥  =  𝑏  →  ( 𝑇 ‘ 𝑥 )  =  ( 𝑇 ‘ 𝑏 ) ) | 
						
							| 46 | 45 | rneqd | ⊢ ( 𝑥  =  𝑏  →  ran  ( 𝑇 ‘ 𝑥 )  =  ran  ( 𝑇 ‘ 𝑏 ) ) | 
						
							| 47 | 46 | eleq2d | ⊢ ( 𝑥  =  𝑏  →  ( 𝑐  ∈  ran  ( 𝑇 ‘ 𝑥 )  ↔  𝑐  ∈  ran  ( 𝑇 ‘ 𝑏 ) ) ) | 
						
							| 48 | 47 | cbvrexvw | ⊢ ( ∃ 𝑥  ∈  𝑊 𝑐  ∈  ran  ( 𝑇 ‘ 𝑥 )  ↔  ∃ 𝑏  ∈  𝑊 𝑐  ∈  ran  ( 𝑇 ‘ 𝑏 ) ) | 
						
							| 49 | 44 48 | bitri | ⊢ ( 𝑐  ∈  ∪  𝑥  ∈  𝑊 ran  ( 𝑇 ‘ 𝑥 )  ↔  ∃ 𝑏  ∈  𝑊 𝑐  ∈  ran  ( 𝑇 ‘ 𝑏 ) ) | 
						
							| 50 |  | simpl1r | ⊢ ( ( ( ( 𝑑  ∈  ℕ0  ∧  { 𝑎  ∈  𝑊  ∣  ( ♯ ‘ 𝑎 )  <  𝑑 }  ⊆  ran  𝑆 )  ∧  𝑐  ∈  𝑊  ∧  ( ♯ ‘ 𝑐 )  =  𝑑 )  ∧  ( 𝑏  ∈  𝑊  ∧  𝑐  ∈  ran  ( 𝑇 ‘ 𝑏 ) ) )  →  { 𝑎  ∈  𝑊  ∣  ( ♯ ‘ 𝑎 )  <  𝑑 }  ⊆  ran  𝑆 ) | 
						
							| 51 |  | fveq2 | ⊢ ( 𝑎  =  𝑏  →  ( ♯ ‘ 𝑎 )  =  ( ♯ ‘ 𝑏 ) ) | 
						
							| 52 | 51 | breq1d | ⊢ ( 𝑎  =  𝑏  →  ( ( ♯ ‘ 𝑎 )  <  𝑑  ↔  ( ♯ ‘ 𝑏 )  <  𝑑 ) ) | 
						
							| 53 |  | simprl | ⊢ ( ( ( ( 𝑑  ∈  ℕ0  ∧  { 𝑎  ∈  𝑊  ∣  ( ♯ ‘ 𝑎 )  <  𝑑 }  ⊆  ran  𝑆 )  ∧  𝑐  ∈  𝑊  ∧  ( ♯ ‘ 𝑐 )  =  𝑑 )  ∧  ( 𝑏  ∈  𝑊  ∧  𝑐  ∈  ran  ( 𝑇 ‘ 𝑏 ) ) )  →  𝑏  ∈  𝑊 ) | 
						
							| 54 | 14 53 | sselid | ⊢ ( ( ( ( 𝑑  ∈  ℕ0  ∧  { 𝑎  ∈  𝑊  ∣  ( ♯ ‘ 𝑎 )  <  𝑑 }  ⊆  ran  𝑆 )  ∧  𝑐  ∈  𝑊  ∧  ( ♯ ‘ 𝑐 )  =  𝑑 )  ∧  ( 𝑏  ∈  𝑊  ∧  𝑐  ∈  ran  ( 𝑇 ‘ 𝑏 ) ) )  →  𝑏  ∈  Word  ( 𝐼  ×  2o ) ) | 
						
							| 55 |  | lencl | ⊢ ( 𝑏  ∈  Word  ( 𝐼  ×  2o )  →  ( ♯ ‘ 𝑏 )  ∈  ℕ0 ) | 
						
							| 56 | 54 55 | syl | ⊢ ( ( ( ( 𝑑  ∈  ℕ0  ∧  { 𝑎  ∈  𝑊  ∣  ( ♯ ‘ 𝑎 )  <  𝑑 }  ⊆  ran  𝑆 )  ∧  𝑐  ∈  𝑊  ∧  ( ♯ ‘ 𝑐 )  =  𝑑 )  ∧  ( 𝑏  ∈  𝑊  ∧  𝑐  ∈  ran  ( 𝑇 ‘ 𝑏 ) ) )  →  ( ♯ ‘ 𝑏 )  ∈  ℕ0 ) | 
						
							| 57 | 56 | nn0red | ⊢ ( ( ( ( 𝑑  ∈  ℕ0  ∧  { 𝑎  ∈  𝑊  ∣  ( ♯ ‘ 𝑎 )  <  𝑑 }  ⊆  ran  𝑆 )  ∧  𝑐  ∈  𝑊  ∧  ( ♯ ‘ 𝑐 )  =  𝑑 )  ∧  ( 𝑏  ∈  𝑊  ∧  𝑐  ∈  ran  ( 𝑇 ‘ 𝑏 ) ) )  →  ( ♯ ‘ 𝑏 )  ∈  ℝ ) | 
						
							| 58 |  | 2rp | ⊢ 2  ∈  ℝ+ | 
						
							| 59 |  | ltaddrp | ⊢ ( ( ( ♯ ‘ 𝑏 )  ∈  ℝ  ∧  2  ∈  ℝ+ )  →  ( ♯ ‘ 𝑏 )  <  ( ( ♯ ‘ 𝑏 )  +  2 ) ) | 
						
							| 60 | 57 58 59 | sylancl | ⊢ ( ( ( ( 𝑑  ∈  ℕ0  ∧  { 𝑎  ∈  𝑊  ∣  ( ♯ ‘ 𝑎 )  <  𝑑 }  ⊆  ran  𝑆 )  ∧  𝑐  ∈  𝑊  ∧  ( ♯ ‘ 𝑐 )  =  𝑑 )  ∧  ( 𝑏  ∈  𝑊  ∧  𝑐  ∈  ran  ( 𝑇 ‘ 𝑏 ) ) )  →  ( ♯ ‘ 𝑏 )  <  ( ( ♯ ‘ 𝑏 )  +  2 ) ) | 
						
							| 61 | 1 2 3 4 | efgtlen | ⊢ ( ( 𝑏  ∈  𝑊  ∧  𝑐  ∈  ran  ( 𝑇 ‘ 𝑏 ) )  →  ( ♯ ‘ 𝑐 )  =  ( ( ♯ ‘ 𝑏 )  +  2 ) ) | 
						
							| 62 | 61 | adantl | ⊢ ( ( ( ( 𝑑  ∈  ℕ0  ∧  { 𝑎  ∈  𝑊  ∣  ( ♯ ‘ 𝑎 )  <  𝑑 }  ⊆  ran  𝑆 )  ∧  𝑐  ∈  𝑊  ∧  ( ♯ ‘ 𝑐 )  =  𝑑 )  ∧  ( 𝑏  ∈  𝑊  ∧  𝑐  ∈  ran  ( 𝑇 ‘ 𝑏 ) ) )  →  ( ♯ ‘ 𝑐 )  =  ( ( ♯ ‘ 𝑏 )  +  2 ) ) | 
						
							| 63 |  | simpl3 | ⊢ ( ( ( ( 𝑑  ∈  ℕ0  ∧  { 𝑎  ∈  𝑊  ∣  ( ♯ ‘ 𝑎 )  <  𝑑 }  ⊆  ran  𝑆 )  ∧  𝑐  ∈  𝑊  ∧  ( ♯ ‘ 𝑐 )  =  𝑑 )  ∧  ( 𝑏  ∈  𝑊  ∧  𝑐  ∈  ran  ( 𝑇 ‘ 𝑏 ) ) )  →  ( ♯ ‘ 𝑐 )  =  𝑑 ) | 
						
							| 64 | 62 63 | eqtr3d | ⊢ ( ( ( ( 𝑑  ∈  ℕ0  ∧  { 𝑎  ∈  𝑊  ∣  ( ♯ ‘ 𝑎 )  <  𝑑 }  ⊆  ran  𝑆 )  ∧  𝑐  ∈  𝑊  ∧  ( ♯ ‘ 𝑐 )  =  𝑑 )  ∧  ( 𝑏  ∈  𝑊  ∧  𝑐  ∈  ran  ( 𝑇 ‘ 𝑏 ) ) )  →  ( ( ♯ ‘ 𝑏 )  +  2 )  =  𝑑 ) | 
						
							| 65 | 60 64 | breqtrd | ⊢ ( ( ( ( 𝑑  ∈  ℕ0  ∧  { 𝑎  ∈  𝑊  ∣  ( ♯ ‘ 𝑎 )  <  𝑑 }  ⊆  ran  𝑆 )  ∧  𝑐  ∈  𝑊  ∧  ( ♯ ‘ 𝑐 )  =  𝑑 )  ∧  ( 𝑏  ∈  𝑊  ∧  𝑐  ∈  ran  ( 𝑇 ‘ 𝑏 ) ) )  →  ( ♯ ‘ 𝑏 )  <  𝑑 ) | 
						
							| 66 | 52 53 65 | elrabd | ⊢ ( ( ( ( 𝑑  ∈  ℕ0  ∧  { 𝑎  ∈  𝑊  ∣  ( ♯ ‘ 𝑎 )  <  𝑑 }  ⊆  ran  𝑆 )  ∧  𝑐  ∈  𝑊  ∧  ( ♯ ‘ 𝑐 )  =  𝑑 )  ∧  ( 𝑏  ∈  𝑊  ∧  𝑐  ∈  ran  ( 𝑇 ‘ 𝑏 ) ) )  →  𝑏  ∈  { 𝑎  ∈  𝑊  ∣  ( ♯ ‘ 𝑎 )  <  𝑑 } ) | 
						
							| 67 | 50 66 | sseldd | ⊢ ( ( ( ( 𝑑  ∈  ℕ0  ∧  { 𝑎  ∈  𝑊  ∣  ( ♯ ‘ 𝑎 )  <  𝑑 }  ⊆  ran  𝑆 )  ∧  𝑐  ∈  𝑊  ∧  ( ♯ ‘ 𝑐 )  =  𝑑 )  ∧  ( 𝑏  ∈  𝑊  ∧  𝑐  ∈  ran  ( 𝑇 ‘ 𝑏 ) ) )  →  𝑏  ∈  ran  𝑆 ) | 
						
							| 68 |  | ffn | ⊢ ( 𝑆 : dom  𝑆 ⟶ 𝑊  →  𝑆  Fn  dom  𝑆 ) | 
						
							| 69 | 10 68 | ax-mp | ⊢ 𝑆  Fn  dom  𝑆 | 
						
							| 70 |  | fvelrnb | ⊢ ( 𝑆  Fn  dom  𝑆  →  ( 𝑏  ∈  ran  𝑆  ↔  ∃ 𝑜  ∈  dom  𝑆 ( 𝑆 ‘ 𝑜 )  =  𝑏 ) ) | 
						
							| 71 | 69 70 | ax-mp | ⊢ ( 𝑏  ∈  ran  𝑆  ↔  ∃ 𝑜  ∈  dom  𝑆 ( 𝑆 ‘ 𝑜 )  =  𝑏 ) | 
						
							| 72 | 67 71 | sylib | ⊢ ( ( ( ( 𝑑  ∈  ℕ0  ∧  { 𝑎  ∈  𝑊  ∣  ( ♯ ‘ 𝑎 )  <  𝑑 }  ⊆  ran  𝑆 )  ∧  𝑐  ∈  𝑊  ∧  ( ♯ ‘ 𝑐 )  =  𝑑 )  ∧  ( 𝑏  ∈  𝑊  ∧  𝑐  ∈  ran  ( 𝑇 ‘ 𝑏 ) ) )  →  ∃ 𝑜  ∈  dom  𝑆 ( 𝑆 ‘ 𝑜 )  =  𝑏 ) | 
						
							| 73 |  | simprrl | ⊢ ( ( ( ( 𝑑  ∈  ℕ0  ∧  { 𝑎  ∈  𝑊  ∣  ( ♯ ‘ 𝑎 )  <  𝑑 }  ⊆  ran  𝑆 )  ∧  𝑐  ∈  𝑊  ∧  ( ♯ ‘ 𝑐 )  =  𝑑 )  ∧  ( ( 𝑏  ∈  𝑊  ∧  𝑐  ∈  ran  ( 𝑇 ‘ 𝑏 ) )  ∧  ( 𝑜  ∈  dom  𝑆  ∧  ( 𝑆 ‘ 𝑜 )  =  𝑏 ) ) )  →  𝑜  ∈  dom  𝑆 ) | 
						
							| 74 | 1 2 3 4 5 6 | efgsdm | ⊢ ( 𝑜  ∈  dom  𝑆  ↔  ( 𝑜  ∈  ( Word  𝑊  ∖  { ∅ } )  ∧  ( 𝑜 ‘ 0 )  ∈  𝐷  ∧  ∀ 𝑖  ∈  ( 1 ..^ ( ♯ ‘ 𝑜 ) ) ( 𝑜 ‘ 𝑖 )  ∈  ran  ( 𝑇 ‘ ( 𝑜 ‘ ( 𝑖  −  1 ) ) ) ) ) | 
						
							| 75 | 74 | simp1bi | ⊢ ( 𝑜  ∈  dom  𝑆  →  𝑜  ∈  ( Word  𝑊  ∖  { ∅ } ) ) | 
						
							| 76 |  | eldifi | ⊢ ( 𝑜  ∈  ( Word  𝑊  ∖  { ∅ } )  →  𝑜  ∈  Word  𝑊 ) | 
						
							| 77 | 73 75 76 | 3syl | ⊢ ( ( ( ( 𝑑  ∈  ℕ0  ∧  { 𝑎  ∈  𝑊  ∣  ( ♯ ‘ 𝑎 )  <  𝑑 }  ⊆  ran  𝑆 )  ∧  𝑐  ∈  𝑊  ∧  ( ♯ ‘ 𝑐 )  =  𝑑 )  ∧  ( ( 𝑏  ∈  𝑊  ∧  𝑐  ∈  ran  ( 𝑇 ‘ 𝑏 ) )  ∧  ( 𝑜  ∈  dom  𝑆  ∧  ( 𝑆 ‘ 𝑜 )  =  𝑏 ) ) )  →  𝑜  ∈  Word  𝑊 ) | 
						
							| 78 |  | simpl2 | ⊢ ( ( ( ( 𝑑  ∈  ℕ0  ∧  { 𝑎  ∈  𝑊  ∣  ( ♯ ‘ 𝑎 )  <  𝑑 }  ⊆  ran  𝑆 )  ∧  𝑐  ∈  𝑊  ∧  ( ♯ ‘ 𝑐 )  =  𝑑 )  ∧  ( ( 𝑏  ∈  𝑊  ∧  𝑐  ∈  ran  ( 𝑇 ‘ 𝑏 ) )  ∧  ( 𝑜  ∈  dom  𝑆  ∧  ( 𝑆 ‘ 𝑜 )  =  𝑏 ) ) )  →  𝑐  ∈  𝑊 ) | 
						
							| 79 |  | simprlr | ⊢ ( ( ( ( 𝑑  ∈  ℕ0  ∧  { 𝑎  ∈  𝑊  ∣  ( ♯ ‘ 𝑎 )  <  𝑑 }  ⊆  ran  𝑆 )  ∧  𝑐  ∈  𝑊  ∧  ( ♯ ‘ 𝑐 )  =  𝑑 )  ∧  ( ( 𝑏  ∈  𝑊  ∧  𝑐  ∈  ran  ( 𝑇 ‘ 𝑏 ) )  ∧  ( 𝑜  ∈  dom  𝑆  ∧  ( 𝑆 ‘ 𝑜 )  =  𝑏 ) ) )  →  𝑐  ∈  ran  ( 𝑇 ‘ 𝑏 ) ) | 
						
							| 80 |  | simprrr | ⊢ ( ( ( ( 𝑑  ∈  ℕ0  ∧  { 𝑎  ∈  𝑊  ∣  ( ♯ ‘ 𝑎 )  <  𝑑 }  ⊆  ran  𝑆 )  ∧  𝑐  ∈  𝑊  ∧  ( ♯ ‘ 𝑐 )  =  𝑑 )  ∧  ( ( 𝑏  ∈  𝑊  ∧  𝑐  ∈  ran  ( 𝑇 ‘ 𝑏 ) )  ∧  ( 𝑜  ∈  dom  𝑆  ∧  ( 𝑆 ‘ 𝑜 )  =  𝑏 ) ) )  →  ( 𝑆 ‘ 𝑜 )  =  𝑏 ) | 
						
							| 81 | 80 | fveq2d | ⊢ ( ( ( ( 𝑑  ∈  ℕ0  ∧  { 𝑎  ∈  𝑊  ∣  ( ♯ ‘ 𝑎 )  <  𝑑 }  ⊆  ran  𝑆 )  ∧  𝑐  ∈  𝑊  ∧  ( ♯ ‘ 𝑐 )  =  𝑑 )  ∧  ( ( 𝑏  ∈  𝑊  ∧  𝑐  ∈  ran  ( 𝑇 ‘ 𝑏 ) )  ∧  ( 𝑜  ∈  dom  𝑆  ∧  ( 𝑆 ‘ 𝑜 )  =  𝑏 ) ) )  →  ( 𝑇 ‘ ( 𝑆 ‘ 𝑜 ) )  =  ( 𝑇 ‘ 𝑏 ) ) | 
						
							| 82 | 81 | rneqd | ⊢ ( ( ( ( 𝑑  ∈  ℕ0  ∧  { 𝑎  ∈  𝑊  ∣  ( ♯ ‘ 𝑎 )  <  𝑑 }  ⊆  ran  𝑆 )  ∧  𝑐  ∈  𝑊  ∧  ( ♯ ‘ 𝑐 )  =  𝑑 )  ∧  ( ( 𝑏  ∈  𝑊  ∧  𝑐  ∈  ran  ( 𝑇 ‘ 𝑏 ) )  ∧  ( 𝑜  ∈  dom  𝑆  ∧  ( 𝑆 ‘ 𝑜 )  =  𝑏 ) ) )  →  ran  ( 𝑇 ‘ ( 𝑆 ‘ 𝑜 ) )  =  ran  ( 𝑇 ‘ 𝑏 ) ) | 
						
							| 83 | 79 82 | eleqtrrd | ⊢ ( ( ( ( 𝑑  ∈  ℕ0  ∧  { 𝑎  ∈  𝑊  ∣  ( ♯ ‘ 𝑎 )  <  𝑑 }  ⊆  ran  𝑆 )  ∧  𝑐  ∈  𝑊  ∧  ( ♯ ‘ 𝑐 )  =  𝑑 )  ∧  ( ( 𝑏  ∈  𝑊  ∧  𝑐  ∈  ran  ( 𝑇 ‘ 𝑏 ) )  ∧  ( 𝑜  ∈  dom  𝑆  ∧  ( 𝑆 ‘ 𝑜 )  =  𝑏 ) ) )  →  𝑐  ∈  ran  ( 𝑇 ‘ ( 𝑆 ‘ 𝑜 ) ) ) | 
						
							| 84 | 1 2 3 4 5 6 | efgsp1 | ⊢ ( ( 𝑜  ∈  dom  𝑆  ∧  𝑐  ∈  ran  ( 𝑇 ‘ ( 𝑆 ‘ 𝑜 ) ) )  →  ( 𝑜  ++  〈“ 𝑐 ”〉 )  ∈  dom  𝑆 ) | 
						
							| 85 | 73 83 84 | syl2anc | ⊢ ( ( ( ( 𝑑  ∈  ℕ0  ∧  { 𝑎  ∈  𝑊  ∣  ( ♯ ‘ 𝑎 )  <  𝑑 }  ⊆  ran  𝑆 )  ∧  𝑐  ∈  𝑊  ∧  ( ♯ ‘ 𝑐 )  =  𝑑 )  ∧  ( ( 𝑏  ∈  𝑊  ∧  𝑐  ∈  ran  ( 𝑇 ‘ 𝑏 ) )  ∧  ( 𝑜  ∈  dom  𝑆  ∧  ( 𝑆 ‘ 𝑜 )  =  𝑏 ) ) )  →  ( 𝑜  ++  〈“ 𝑐 ”〉 )  ∈  dom  𝑆 ) | 
						
							| 86 | 1 2 3 4 5 6 | efgsval2 | ⊢ ( ( 𝑜  ∈  Word  𝑊  ∧  𝑐  ∈  𝑊  ∧  ( 𝑜  ++  〈“ 𝑐 ”〉 )  ∈  dom  𝑆 )  →  ( 𝑆 ‘ ( 𝑜  ++  〈“ 𝑐 ”〉 ) )  =  𝑐 ) | 
						
							| 87 | 77 78 85 86 | syl3anc | ⊢ ( ( ( ( 𝑑  ∈  ℕ0  ∧  { 𝑎  ∈  𝑊  ∣  ( ♯ ‘ 𝑎 )  <  𝑑 }  ⊆  ran  𝑆 )  ∧  𝑐  ∈  𝑊  ∧  ( ♯ ‘ 𝑐 )  =  𝑑 )  ∧  ( ( 𝑏  ∈  𝑊  ∧  𝑐  ∈  ran  ( 𝑇 ‘ 𝑏 ) )  ∧  ( 𝑜  ∈  dom  𝑆  ∧  ( 𝑆 ‘ 𝑜 )  =  𝑏 ) ) )  →  ( 𝑆 ‘ ( 𝑜  ++  〈“ 𝑐 ”〉 ) )  =  𝑐 ) | 
						
							| 88 |  | fnfvelrn | ⊢ ( ( 𝑆  Fn  dom  𝑆  ∧  ( 𝑜  ++  〈“ 𝑐 ”〉 )  ∈  dom  𝑆 )  →  ( 𝑆 ‘ ( 𝑜  ++  〈“ 𝑐 ”〉 ) )  ∈  ran  𝑆 ) | 
						
							| 89 | 69 85 88 | sylancr | ⊢ ( ( ( ( 𝑑  ∈  ℕ0  ∧  { 𝑎  ∈  𝑊  ∣  ( ♯ ‘ 𝑎 )  <  𝑑 }  ⊆  ran  𝑆 )  ∧  𝑐  ∈  𝑊  ∧  ( ♯ ‘ 𝑐 )  =  𝑑 )  ∧  ( ( 𝑏  ∈  𝑊  ∧  𝑐  ∈  ran  ( 𝑇 ‘ 𝑏 ) )  ∧  ( 𝑜  ∈  dom  𝑆  ∧  ( 𝑆 ‘ 𝑜 )  =  𝑏 ) ) )  →  ( 𝑆 ‘ ( 𝑜  ++  〈“ 𝑐 ”〉 ) )  ∈  ran  𝑆 ) | 
						
							| 90 | 87 89 | eqeltrrd | ⊢ ( ( ( ( 𝑑  ∈  ℕ0  ∧  { 𝑎  ∈  𝑊  ∣  ( ♯ ‘ 𝑎 )  <  𝑑 }  ⊆  ran  𝑆 )  ∧  𝑐  ∈  𝑊  ∧  ( ♯ ‘ 𝑐 )  =  𝑑 )  ∧  ( ( 𝑏  ∈  𝑊  ∧  𝑐  ∈  ran  ( 𝑇 ‘ 𝑏 ) )  ∧  ( 𝑜  ∈  dom  𝑆  ∧  ( 𝑆 ‘ 𝑜 )  =  𝑏 ) ) )  →  𝑐  ∈  ran  𝑆 ) | 
						
							| 91 | 90 | anassrs | ⊢ ( ( ( ( ( 𝑑  ∈  ℕ0  ∧  { 𝑎  ∈  𝑊  ∣  ( ♯ ‘ 𝑎 )  <  𝑑 }  ⊆  ran  𝑆 )  ∧  𝑐  ∈  𝑊  ∧  ( ♯ ‘ 𝑐 )  =  𝑑 )  ∧  ( 𝑏  ∈  𝑊  ∧  𝑐  ∈  ran  ( 𝑇 ‘ 𝑏 ) ) )  ∧  ( 𝑜  ∈  dom  𝑆  ∧  ( 𝑆 ‘ 𝑜 )  =  𝑏 ) )  →  𝑐  ∈  ran  𝑆 ) | 
						
							| 92 | 72 91 | rexlimddv | ⊢ ( ( ( ( 𝑑  ∈  ℕ0  ∧  { 𝑎  ∈  𝑊  ∣  ( ♯ ‘ 𝑎 )  <  𝑑 }  ⊆  ran  𝑆 )  ∧  𝑐  ∈  𝑊  ∧  ( ♯ ‘ 𝑐 )  =  𝑑 )  ∧  ( 𝑏  ∈  𝑊  ∧  𝑐  ∈  ran  ( 𝑇 ‘ 𝑏 ) ) )  →  𝑐  ∈  ran  𝑆 ) | 
						
							| 93 | 92 | rexlimdvaa | ⊢ ( ( ( 𝑑  ∈  ℕ0  ∧  { 𝑎  ∈  𝑊  ∣  ( ♯ ‘ 𝑎 )  <  𝑑 }  ⊆  ran  𝑆 )  ∧  𝑐  ∈  𝑊  ∧  ( ♯ ‘ 𝑐 )  =  𝑑 )  →  ( ∃ 𝑏  ∈  𝑊 𝑐  ∈  ran  ( 𝑇 ‘ 𝑏 )  →  𝑐  ∈  ran  𝑆 ) ) | 
						
							| 94 | 49 93 | biimtrid | ⊢ ( ( ( 𝑑  ∈  ℕ0  ∧  { 𝑎  ∈  𝑊  ∣  ( ♯ ‘ 𝑎 )  <  𝑑 }  ⊆  ran  𝑆 )  ∧  𝑐  ∈  𝑊  ∧  ( ♯ ‘ 𝑐 )  =  𝑑 )  →  ( 𝑐  ∈  ∪  𝑥  ∈  𝑊 ran  ( 𝑇 ‘ 𝑥 )  →  𝑐  ∈  ran  𝑆 ) ) | 
						
							| 95 |  | eldif | ⊢ ( 𝑐  ∈  ( 𝑊  ∖  ∪  𝑥  ∈  𝑊 ran  ( 𝑇 ‘ 𝑥 ) )  ↔  ( 𝑐  ∈  𝑊  ∧  ¬  𝑐  ∈  ∪  𝑥  ∈  𝑊 ran  ( 𝑇 ‘ 𝑥 ) ) ) | 
						
							| 96 | 5 | eleq2i | ⊢ ( 𝑐  ∈  𝐷  ↔  𝑐  ∈  ( 𝑊  ∖  ∪  𝑥  ∈  𝑊 ran  ( 𝑇 ‘ 𝑥 ) ) ) | 
						
							| 97 | 1 2 3 4 5 6 | efgs1 | ⊢ ( 𝑐  ∈  𝐷  →  〈“ 𝑐 ”〉  ∈  dom  𝑆 ) | 
						
							| 98 | 96 97 | sylbir | ⊢ ( 𝑐  ∈  ( 𝑊  ∖  ∪  𝑥  ∈  𝑊 ran  ( 𝑇 ‘ 𝑥 ) )  →  〈“ 𝑐 ”〉  ∈  dom  𝑆 ) | 
						
							| 99 | 95 98 | sylbir | ⊢ ( ( 𝑐  ∈  𝑊  ∧  ¬  𝑐  ∈  ∪  𝑥  ∈  𝑊 ran  ( 𝑇 ‘ 𝑥 ) )  →  〈“ 𝑐 ”〉  ∈  dom  𝑆 ) | 
						
							| 100 | 1 2 3 4 5 6 | efgsval | ⊢ ( 〈“ 𝑐 ”〉  ∈  dom  𝑆  →  ( 𝑆 ‘ 〈“ 𝑐 ”〉 )  =  ( 〈“ 𝑐 ”〉 ‘ ( ( ♯ ‘ 〈“ 𝑐 ”〉 )  −  1 ) ) ) | 
						
							| 101 | 99 100 | syl | ⊢ ( ( 𝑐  ∈  𝑊  ∧  ¬  𝑐  ∈  ∪  𝑥  ∈  𝑊 ran  ( 𝑇 ‘ 𝑥 ) )  →  ( 𝑆 ‘ 〈“ 𝑐 ”〉 )  =  ( 〈“ 𝑐 ”〉 ‘ ( ( ♯ ‘ 〈“ 𝑐 ”〉 )  −  1 ) ) ) | 
						
							| 102 |  | s1len | ⊢ ( ♯ ‘ 〈“ 𝑐 ”〉 )  =  1 | 
						
							| 103 | 102 | oveq1i | ⊢ ( ( ♯ ‘ 〈“ 𝑐 ”〉 )  −  1 )  =  ( 1  −  1 ) | 
						
							| 104 |  | 1m1e0 | ⊢ ( 1  −  1 )  =  0 | 
						
							| 105 | 103 104 | eqtri | ⊢ ( ( ♯ ‘ 〈“ 𝑐 ”〉 )  −  1 )  =  0 | 
						
							| 106 | 105 | fveq2i | ⊢ ( 〈“ 𝑐 ”〉 ‘ ( ( ♯ ‘ 〈“ 𝑐 ”〉 )  −  1 ) )  =  ( 〈“ 𝑐 ”〉 ‘ 0 ) | 
						
							| 107 | 106 | a1i | ⊢ ( ( 𝑐  ∈  𝑊  ∧  ¬  𝑐  ∈  ∪  𝑥  ∈  𝑊 ran  ( 𝑇 ‘ 𝑥 ) )  →  ( 〈“ 𝑐 ”〉 ‘ ( ( ♯ ‘ 〈“ 𝑐 ”〉 )  −  1 ) )  =  ( 〈“ 𝑐 ”〉 ‘ 0 ) ) | 
						
							| 108 |  | s1fv | ⊢ ( 𝑐  ∈  𝑊  →  ( 〈“ 𝑐 ”〉 ‘ 0 )  =  𝑐 ) | 
						
							| 109 | 108 | adantr | ⊢ ( ( 𝑐  ∈  𝑊  ∧  ¬  𝑐  ∈  ∪  𝑥  ∈  𝑊 ran  ( 𝑇 ‘ 𝑥 ) )  →  ( 〈“ 𝑐 ”〉 ‘ 0 )  =  𝑐 ) | 
						
							| 110 | 101 107 109 | 3eqtrd | ⊢ ( ( 𝑐  ∈  𝑊  ∧  ¬  𝑐  ∈  ∪  𝑥  ∈  𝑊 ran  ( 𝑇 ‘ 𝑥 ) )  →  ( 𝑆 ‘ 〈“ 𝑐 ”〉 )  =  𝑐 ) | 
						
							| 111 |  | fnfvelrn | ⊢ ( ( 𝑆  Fn  dom  𝑆  ∧  〈“ 𝑐 ”〉  ∈  dom  𝑆 )  →  ( 𝑆 ‘ 〈“ 𝑐 ”〉 )  ∈  ran  𝑆 ) | 
						
							| 112 | 69 99 111 | sylancr | ⊢ ( ( 𝑐  ∈  𝑊  ∧  ¬  𝑐  ∈  ∪  𝑥  ∈  𝑊 ran  ( 𝑇 ‘ 𝑥 ) )  →  ( 𝑆 ‘ 〈“ 𝑐 ”〉 )  ∈  ran  𝑆 ) | 
						
							| 113 | 110 112 | eqeltrrd | ⊢ ( ( 𝑐  ∈  𝑊  ∧  ¬  𝑐  ∈  ∪  𝑥  ∈  𝑊 ran  ( 𝑇 ‘ 𝑥 ) )  →  𝑐  ∈  ran  𝑆 ) | 
						
							| 114 | 113 | ex | ⊢ ( 𝑐  ∈  𝑊  →  ( ¬  𝑐  ∈  ∪  𝑥  ∈  𝑊 ran  ( 𝑇 ‘ 𝑥 )  →  𝑐  ∈  ran  𝑆 ) ) | 
						
							| 115 | 114 | 3ad2ant2 | ⊢ ( ( ( 𝑑  ∈  ℕ0  ∧  { 𝑎  ∈  𝑊  ∣  ( ♯ ‘ 𝑎 )  <  𝑑 }  ⊆  ran  𝑆 )  ∧  𝑐  ∈  𝑊  ∧  ( ♯ ‘ 𝑐 )  =  𝑑 )  →  ( ¬  𝑐  ∈  ∪  𝑥  ∈  𝑊 ran  ( 𝑇 ‘ 𝑥 )  →  𝑐  ∈  ran  𝑆 ) ) | 
						
							| 116 | 94 115 | pm2.61d | ⊢ ( ( ( 𝑑  ∈  ℕ0  ∧  { 𝑎  ∈  𝑊  ∣  ( ♯ ‘ 𝑎 )  <  𝑑 }  ⊆  ran  𝑆 )  ∧  𝑐  ∈  𝑊  ∧  ( ♯ ‘ 𝑐 )  =  𝑑 )  →  𝑐  ∈  ran  𝑆 ) | 
						
							| 117 | 116 | rabssdv | ⊢ ( ( 𝑑  ∈  ℕ0  ∧  { 𝑎  ∈  𝑊  ∣  ( ♯ ‘ 𝑎 )  <  𝑑 }  ⊆  ran  𝑆 )  →  { 𝑐  ∈  𝑊  ∣  ( ♯ ‘ 𝑐 )  =  𝑑 }  ⊆  ran  𝑆 ) | 
						
							| 118 | 43 117 | eqsstrid | ⊢ ( ( 𝑑  ∈  ℕ0  ∧  { 𝑎  ∈  𝑊  ∣  ( ♯ ‘ 𝑎 )  <  𝑑 }  ⊆  ran  𝑆 )  →  { 𝑎  ∈  𝑊  ∣  ( ♯ ‘ 𝑎 )  =  𝑑 }  ⊆  ran  𝑆 ) | 
						
							| 119 | 41 118 | unssd | ⊢ ( ( 𝑑  ∈  ℕ0  ∧  { 𝑎  ∈  𝑊  ∣  ( ♯ ‘ 𝑎 )  <  𝑑 }  ⊆  ran  𝑆 )  →  ( { 𝑎  ∈  𝑊  ∣  ( ♯ ‘ 𝑎 )  <  𝑑 }  ∪  { 𝑎  ∈  𝑊  ∣  ( ♯ ‘ 𝑎 )  =  𝑑 } )  ⊆  ran  𝑆 ) | 
						
							| 120 | 119 | ex | ⊢ ( 𝑑  ∈  ℕ0  →  ( { 𝑎  ∈  𝑊  ∣  ( ♯ ‘ 𝑎 )  <  𝑑 }  ⊆  ran  𝑆  →  ( { 𝑎  ∈  𝑊  ∣  ( ♯ ‘ 𝑎 )  <  𝑑 }  ∪  { 𝑎  ∈  𝑊  ∣  ( ♯ ‘ 𝑎 )  =  𝑑 } )  ⊆  ran  𝑆 ) ) | 
						
							| 121 |  | id | ⊢ ( 𝑑  ∈  ℕ0  →  𝑑  ∈  ℕ0 ) | 
						
							| 122 |  | nn0leltp1 | ⊢ ( ( ( ♯ ‘ 𝑎 )  ∈  ℕ0  ∧  𝑑  ∈  ℕ0 )  →  ( ( ♯ ‘ 𝑎 )  ≤  𝑑  ↔  ( ♯ ‘ 𝑎 )  <  ( 𝑑  +  1 ) ) ) | 
						
							| 123 | 21 121 122 | syl2anr | ⊢ ( ( 𝑑  ∈  ℕ0  ∧  𝑎  ∈  𝑊 )  →  ( ( ♯ ‘ 𝑎 )  ≤  𝑑  ↔  ( ♯ ‘ 𝑎 )  <  ( 𝑑  +  1 ) ) ) | 
						
							| 124 | 21 | nn0red | ⊢ ( 𝑎  ∈  𝑊  →  ( ♯ ‘ 𝑎 )  ∈  ℝ ) | 
						
							| 125 |  | nn0re | ⊢ ( 𝑑  ∈  ℕ0  →  𝑑  ∈  ℝ ) | 
						
							| 126 |  | leloe | ⊢ ( ( ( ♯ ‘ 𝑎 )  ∈  ℝ  ∧  𝑑  ∈  ℝ )  →  ( ( ♯ ‘ 𝑎 )  ≤  𝑑  ↔  ( ( ♯ ‘ 𝑎 )  <  𝑑  ∨  ( ♯ ‘ 𝑎 )  =  𝑑 ) ) ) | 
						
							| 127 | 124 125 126 | syl2anr | ⊢ ( ( 𝑑  ∈  ℕ0  ∧  𝑎  ∈  𝑊 )  →  ( ( ♯ ‘ 𝑎 )  ≤  𝑑  ↔  ( ( ♯ ‘ 𝑎 )  <  𝑑  ∨  ( ♯ ‘ 𝑎 )  =  𝑑 ) ) ) | 
						
							| 128 | 123 127 | bitr3d | ⊢ ( ( 𝑑  ∈  ℕ0  ∧  𝑎  ∈  𝑊 )  →  ( ( ♯ ‘ 𝑎 )  <  ( 𝑑  +  1 )  ↔  ( ( ♯ ‘ 𝑎 )  <  𝑑  ∨  ( ♯ ‘ 𝑎 )  =  𝑑 ) ) ) | 
						
							| 129 | 128 | rabbidva | ⊢ ( 𝑑  ∈  ℕ0  →  { 𝑎  ∈  𝑊  ∣  ( ♯ ‘ 𝑎 )  <  ( 𝑑  +  1 ) }  =  { 𝑎  ∈  𝑊  ∣  ( ( ♯ ‘ 𝑎 )  <  𝑑  ∨  ( ♯ ‘ 𝑎 )  =  𝑑 ) } ) | 
						
							| 130 |  | unrab | ⊢ ( { 𝑎  ∈  𝑊  ∣  ( ♯ ‘ 𝑎 )  <  𝑑 }  ∪  { 𝑎  ∈  𝑊  ∣  ( ♯ ‘ 𝑎 )  =  𝑑 } )  =  { 𝑎  ∈  𝑊  ∣  ( ( ♯ ‘ 𝑎 )  <  𝑑  ∨  ( ♯ ‘ 𝑎 )  =  𝑑 ) } | 
						
							| 131 | 129 130 | eqtr4di | ⊢ ( 𝑑  ∈  ℕ0  →  { 𝑎  ∈  𝑊  ∣  ( ♯ ‘ 𝑎 )  <  ( 𝑑  +  1 ) }  =  ( { 𝑎  ∈  𝑊  ∣  ( ♯ ‘ 𝑎 )  <  𝑑 }  ∪  { 𝑎  ∈  𝑊  ∣  ( ♯ ‘ 𝑎 )  =  𝑑 } ) ) | 
						
							| 132 | 131 | sseq1d | ⊢ ( 𝑑  ∈  ℕ0  →  ( { 𝑎  ∈  𝑊  ∣  ( ♯ ‘ 𝑎 )  <  ( 𝑑  +  1 ) }  ⊆  ran  𝑆  ↔  ( { 𝑎  ∈  𝑊  ∣  ( ♯ ‘ 𝑎 )  <  𝑑 }  ∪  { 𝑎  ∈  𝑊  ∣  ( ♯ ‘ 𝑎 )  =  𝑑 } )  ⊆  ran  𝑆 ) ) | 
						
							| 133 | 120 132 | sylibrd | ⊢ ( 𝑑  ∈  ℕ0  →  ( { 𝑎  ∈  𝑊  ∣  ( ♯ ‘ 𝑎 )  <  𝑑 }  ⊆  ran  𝑆  →  { 𝑎  ∈  𝑊  ∣  ( ♯ ‘ 𝑎 )  <  ( 𝑑  +  1 ) }  ⊆  ran  𝑆 ) ) | 
						
							| 134 | 30 33 36 39 40 133 | nn0ind | ⊢ ( ( ( ♯ ‘ 𝑐 )  +  1 )  ∈  ℕ0  →  { 𝑎  ∈  𝑊  ∣  ( ♯ ‘ 𝑎 )  <  ( ( ♯ ‘ 𝑐 )  +  1 ) }  ⊆  ran  𝑆 ) | 
						
							| 135 | 17 18 134 | 3syl | ⊢ ( 𝑐  ∈  𝑊  →  { 𝑎  ∈  𝑊  ∣  ( ♯ ‘ 𝑎 )  <  ( ( ♯ ‘ 𝑐 )  +  1 ) }  ⊆  ran  𝑆 ) | 
						
							| 136 |  | fveq2 | ⊢ ( 𝑎  =  𝑐  →  ( ♯ ‘ 𝑎 )  =  ( ♯ ‘ 𝑐 ) ) | 
						
							| 137 | 136 | breq1d | ⊢ ( 𝑎  =  𝑐  →  ( ( ♯ ‘ 𝑎 )  <  ( ( ♯ ‘ 𝑐 )  +  1 )  ↔  ( ♯ ‘ 𝑐 )  <  ( ( ♯ ‘ 𝑐 )  +  1 ) ) ) | 
						
							| 138 |  | id | ⊢ ( 𝑐  ∈  𝑊  →  𝑐  ∈  𝑊 ) | 
						
							| 139 | 17 | nn0red | ⊢ ( 𝑐  ∈  𝑊  →  ( ♯ ‘ 𝑐 )  ∈  ℝ ) | 
						
							| 140 | 139 | ltp1d | ⊢ ( 𝑐  ∈  𝑊  →  ( ♯ ‘ 𝑐 )  <  ( ( ♯ ‘ 𝑐 )  +  1 ) ) | 
						
							| 141 | 137 138 140 | elrabd | ⊢ ( 𝑐  ∈  𝑊  →  𝑐  ∈  { 𝑎  ∈  𝑊  ∣  ( ♯ ‘ 𝑎 )  <  ( ( ♯ ‘ 𝑐 )  +  1 ) } ) | 
						
							| 142 | 135 141 | sseldd | ⊢ ( 𝑐  ∈  𝑊  →  𝑐  ∈  ran  𝑆 ) | 
						
							| 143 | 142 | ssriv | ⊢ 𝑊  ⊆  ran  𝑆 | 
						
							| 144 | 12 143 | eqssi | ⊢ ran  𝑆  =  𝑊 | 
						
							| 145 |  | dffo2 | ⊢ ( 𝑆 : dom  𝑆 –onto→ 𝑊  ↔  ( 𝑆 : dom  𝑆 ⟶ 𝑊  ∧  ran  𝑆  =  𝑊 ) ) | 
						
							| 146 | 10 144 145 | mpbir2an | ⊢ 𝑆 : dom  𝑆 –onto→ 𝑊 |