| Step | Hyp | Ref | Expression | 
						
							| 1 |  | eqeq2 | ⊢ ( 𝑥  =  1  →  ( ( #b ‘ 𝑎 )  =  𝑥  ↔  ( #b ‘ 𝑎 )  =  1 ) ) | 
						
							| 2 |  | oveq2 | ⊢ ( 𝑥  =  1  →  ( 0 ..^ 𝑥 )  =  ( 0 ..^ 1 ) ) | 
						
							| 3 |  | fzo01 | ⊢ ( 0 ..^ 1 )  =  { 0 } | 
						
							| 4 | 2 3 | eqtrdi | ⊢ ( 𝑥  =  1  →  ( 0 ..^ 𝑥 )  =  { 0 } ) | 
						
							| 5 | 4 | sumeq1d | ⊢ ( 𝑥  =  1  →  Σ 𝑘  ∈  ( 0 ..^ 𝑥 ) ( ( 𝑘 ( digit ‘ 2 ) 𝑎 )  ·  ( 2 ↑ 𝑘 ) )  =  Σ 𝑘  ∈  { 0 } ( ( 𝑘 ( digit ‘ 2 ) 𝑎 )  ·  ( 2 ↑ 𝑘 ) ) ) | 
						
							| 6 | 5 | eqeq2d | ⊢ ( 𝑥  =  1  →  ( 𝑎  =  Σ 𝑘  ∈  ( 0 ..^ 𝑥 ) ( ( 𝑘 ( digit ‘ 2 ) 𝑎 )  ·  ( 2 ↑ 𝑘 ) )  ↔  𝑎  =  Σ 𝑘  ∈  { 0 } ( ( 𝑘 ( digit ‘ 2 ) 𝑎 )  ·  ( 2 ↑ 𝑘 ) ) ) ) | 
						
							| 7 | 1 6 | imbi12d | ⊢ ( 𝑥  =  1  →  ( ( ( #b ‘ 𝑎 )  =  𝑥  →  𝑎  =  Σ 𝑘  ∈  ( 0 ..^ 𝑥 ) ( ( 𝑘 ( digit ‘ 2 ) 𝑎 )  ·  ( 2 ↑ 𝑘 ) ) )  ↔  ( ( #b ‘ 𝑎 )  =  1  →  𝑎  =  Σ 𝑘  ∈  { 0 } ( ( 𝑘 ( digit ‘ 2 ) 𝑎 )  ·  ( 2 ↑ 𝑘 ) ) ) ) ) | 
						
							| 8 | 7 | ralbidv | ⊢ ( 𝑥  =  1  →  ( ∀ 𝑎  ∈  ℕ0 ( ( #b ‘ 𝑎 )  =  𝑥  →  𝑎  =  Σ 𝑘  ∈  ( 0 ..^ 𝑥 ) ( ( 𝑘 ( digit ‘ 2 ) 𝑎 )  ·  ( 2 ↑ 𝑘 ) ) )  ↔  ∀ 𝑎  ∈  ℕ0 ( ( #b ‘ 𝑎 )  =  1  →  𝑎  =  Σ 𝑘  ∈  { 0 } ( ( 𝑘 ( digit ‘ 2 ) 𝑎 )  ·  ( 2 ↑ 𝑘 ) ) ) ) ) | 
						
							| 9 |  | eqeq2 | ⊢ ( 𝑥  =  𝑦  →  ( ( #b ‘ 𝑎 )  =  𝑥  ↔  ( #b ‘ 𝑎 )  =  𝑦 ) ) | 
						
							| 10 |  | oveq2 | ⊢ ( 𝑥  =  𝑦  →  ( 0 ..^ 𝑥 )  =  ( 0 ..^ 𝑦 ) ) | 
						
							| 11 | 10 | sumeq1d | ⊢ ( 𝑥  =  𝑦  →  Σ 𝑘  ∈  ( 0 ..^ 𝑥 ) ( ( 𝑘 ( digit ‘ 2 ) 𝑎 )  ·  ( 2 ↑ 𝑘 ) )  =  Σ 𝑘  ∈  ( 0 ..^ 𝑦 ) ( ( 𝑘 ( digit ‘ 2 ) 𝑎 )  ·  ( 2 ↑ 𝑘 ) ) ) | 
						
							| 12 | 11 | eqeq2d | ⊢ ( 𝑥  =  𝑦  →  ( 𝑎  =  Σ 𝑘  ∈  ( 0 ..^ 𝑥 ) ( ( 𝑘 ( digit ‘ 2 ) 𝑎 )  ·  ( 2 ↑ 𝑘 ) )  ↔  𝑎  =  Σ 𝑘  ∈  ( 0 ..^ 𝑦 ) ( ( 𝑘 ( digit ‘ 2 ) 𝑎 )  ·  ( 2 ↑ 𝑘 ) ) ) ) | 
						
							| 13 | 9 12 | imbi12d | ⊢ ( 𝑥  =  𝑦  →  ( ( ( #b ‘ 𝑎 )  =  𝑥  →  𝑎  =  Σ 𝑘  ∈  ( 0 ..^ 𝑥 ) ( ( 𝑘 ( digit ‘ 2 ) 𝑎 )  ·  ( 2 ↑ 𝑘 ) ) )  ↔  ( ( #b ‘ 𝑎 )  =  𝑦  →  𝑎  =  Σ 𝑘  ∈  ( 0 ..^ 𝑦 ) ( ( 𝑘 ( digit ‘ 2 ) 𝑎 )  ·  ( 2 ↑ 𝑘 ) ) ) ) ) | 
						
							| 14 | 13 | ralbidv | ⊢ ( 𝑥  =  𝑦  →  ( ∀ 𝑎  ∈  ℕ0 ( ( #b ‘ 𝑎 )  =  𝑥  →  𝑎  =  Σ 𝑘  ∈  ( 0 ..^ 𝑥 ) ( ( 𝑘 ( digit ‘ 2 ) 𝑎 )  ·  ( 2 ↑ 𝑘 ) ) )  ↔  ∀ 𝑎  ∈  ℕ0 ( ( #b ‘ 𝑎 )  =  𝑦  →  𝑎  =  Σ 𝑘  ∈  ( 0 ..^ 𝑦 ) ( ( 𝑘 ( digit ‘ 2 ) 𝑎 )  ·  ( 2 ↑ 𝑘 ) ) ) ) ) | 
						
							| 15 |  | eqeq2 | ⊢ ( 𝑥  =  ( 𝑦  +  1 )  →  ( ( #b ‘ 𝑎 )  =  𝑥  ↔  ( #b ‘ 𝑎 )  =  ( 𝑦  +  1 ) ) ) | 
						
							| 16 |  | oveq2 | ⊢ ( 𝑥  =  ( 𝑦  +  1 )  →  ( 0 ..^ 𝑥 )  =  ( 0 ..^ ( 𝑦  +  1 ) ) ) | 
						
							| 17 | 16 | sumeq1d | ⊢ ( 𝑥  =  ( 𝑦  +  1 )  →  Σ 𝑘  ∈  ( 0 ..^ 𝑥 ) ( ( 𝑘 ( digit ‘ 2 ) 𝑎 )  ·  ( 2 ↑ 𝑘 ) )  =  Σ 𝑘  ∈  ( 0 ..^ ( 𝑦  +  1 ) ) ( ( 𝑘 ( digit ‘ 2 ) 𝑎 )  ·  ( 2 ↑ 𝑘 ) ) ) | 
						
							| 18 | 17 | eqeq2d | ⊢ ( 𝑥  =  ( 𝑦  +  1 )  →  ( 𝑎  =  Σ 𝑘  ∈  ( 0 ..^ 𝑥 ) ( ( 𝑘 ( digit ‘ 2 ) 𝑎 )  ·  ( 2 ↑ 𝑘 ) )  ↔  𝑎  =  Σ 𝑘  ∈  ( 0 ..^ ( 𝑦  +  1 ) ) ( ( 𝑘 ( digit ‘ 2 ) 𝑎 )  ·  ( 2 ↑ 𝑘 ) ) ) ) | 
						
							| 19 | 15 18 | imbi12d | ⊢ ( 𝑥  =  ( 𝑦  +  1 )  →  ( ( ( #b ‘ 𝑎 )  =  𝑥  →  𝑎  =  Σ 𝑘  ∈  ( 0 ..^ 𝑥 ) ( ( 𝑘 ( digit ‘ 2 ) 𝑎 )  ·  ( 2 ↑ 𝑘 ) ) )  ↔  ( ( #b ‘ 𝑎 )  =  ( 𝑦  +  1 )  →  𝑎  =  Σ 𝑘  ∈  ( 0 ..^ ( 𝑦  +  1 ) ) ( ( 𝑘 ( digit ‘ 2 ) 𝑎 )  ·  ( 2 ↑ 𝑘 ) ) ) ) ) | 
						
							| 20 | 19 | ralbidv | ⊢ ( 𝑥  =  ( 𝑦  +  1 )  →  ( ∀ 𝑎  ∈  ℕ0 ( ( #b ‘ 𝑎 )  =  𝑥  →  𝑎  =  Σ 𝑘  ∈  ( 0 ..^ 𝑥 ) ( ( 𝑘 ( digit ‘ 2 ) 𝑎 )  ·  ( 2 ↑ 𝑘 ) ) )  ↔  ∀ 𝑎  ∈  ℕ0 ( ( #b ‘ 𝑎 )  =  ( 𝑦  +  1 )  →  𝑎  =  Σ 𝑘  ∈  ( 0 ..^ ( 𝑦  +  1 ) ) ( ( 𝑘 ( digit ‘ 2 ) 𝑎 )  ·  ( 2 ↑ 𝑘 ) ) ) ) ) | 
						
							| 21 |  | eqeq2 | ⊢ ( 𝑥  =  𝐿  →  ( ( #b ‘ 𝑎 )  =  𝑥  ↔  ( #b ‘ 𝑎 )  =  𝐿 ) ) | 
						
							| 22 |  | oveq2 | ⊢ ( 𝑥  =  𝐿  →  ( 0 ..^ 𝑥 )  =  ( 0 ..^ 𝐿 ) ) | 
						
							| 23 | 22 | sumeq1d | ⊢ ( 𝑥  =  𝐿  →  Σ 𝑘  ∈  ( 0 ..^ 𝑥 ) ( ( 𝑘 ( digit ‘ 2 ) 𝑎 )  ·  ( 2 ↑ 𝑘 ) )  =  Σ 𝑘  ∈  ( 0 ..^ 𝐿 ) ( ( 𝑘 ( digit ‘ 2 ) 𝑎 )  ·  ( 2 ↑ 𝑘 ) ) ) | 
						
							| 24 | 23 | eqeq2d | ⊢ ( 𝑥  =  𝐿  →  ( 𝑎  =  Σ 𝑘  ∈  ( 0 ..^ 𝑥 ) ( ( 𝑘 ( digit ‘ 2 ) 𝑎 )  ·  ( 2 ↑ 𝑘 ) )  ↔  𝑎  =  Σ 𝑘  ∈  ( 0 ..^ 𝐿 ) ( ( 𝑘 ( digit ‘ 2 ) 𝑎 )  ·  ( 2 ↑ 𝑘 ) ) ) ) | 
						
							| 25 | 21 24 | imbi12d | ⊢ ( 𝑥  =  𝐿  →  ( ( ( #b ‘ 𝑎 )  =  𝑥  →  𝑎  =  Σ 𝑘  ∈  ( 0 ..^ 𝑥 ) ( ( 𝑘 ( digit ‘ 2 ) 𝑎 )  ·  ( 2 ↑ 𝑘 ) ) )  ↔  ( ( #b ‘ 𝑎 )  =  𝐿  →  𝑎  =  Σ 𝑘  ∈  ( 0 ..^ 𝐿 ) ( ( 𝑘 ( digit ‘ 2 ) 𝑎 )  ·  ( 2 ↑ 𝑘 ) ) ) ) ) | 
						
							| 26 | 25 | ralbidv | ⊢ ( 𝑥  =  𝐿  →  ( ∀ 𝑎  ∈  ℕ0 ( ( #b ‘ 𝑎 )  =  𝑥  →  𝑎  =  Σ 𝑘  ∈  ( 0 ..^ 𝑥 ) ( ( 𝑘 ( digit ‘ 2 ) 𝑎 )  ·  ( 2 ↑ 𝑘 ) ) )  ↔  ∀ 𝑎  ∈  ℕ0 ( ( #b ‘ 𝑎 )  =  𝐿  →  𝑎  =  Σ 𝑘  ∈  ( 0 ..^ 𝐿 ) ( ( 𝑘 ( digit ‘ 2 ) 𝑎 )  ·  ( 2 ↑ 𝑘 ) ) ) ) ) | 
						
							| 27 |  | 0cnd | ⊢ ( 𝑎  ∈  ℕ0  →  0  ∈  ℂ ) | 
						
							| 28 |  | 2nn | ⊢ 2  ∈  ℕ | 
						
							| 29 | 28 | a1i | ⊢ ( 𝑎  ∈  ℕ0  →  2  ∈  ℕ ) | 
						
							| 30 |  | 0zd | ⊢ ( 𝑎  ∈  ℕ0  →  0  ∈  ℤ ) | 
						
							| 31 |  | nn0rp0 | ⊢ ( 𝑎  ∈  ℕ0  →  𝑎  ∈  ( 0 [,) +∞ ) ) | 
						
							| 32 |  | digvalnn0 | ⊢ ( ( 2  ∈  ℕ  ∧  0  ∈  ℤ  ∧  𝑎  ∈  ( 0 [,) +∞ ) )  →  ( 0 ( digit ‘ 2 ) 𝑎 )  ∈  ℕ0 ) | 
						
							| 33 | 29 30 31 32 | syl3anc | ⊢ ( 𝑎  ∈  ℕ0  →  ( 0 ( digit ‘ 2 ) 𝑎 )  ∈  ℕ0 ) | 
						
							| 34 | 33 | nn0cnd | ⊢ ( 𝑎  ∈  ℕ0  →  ( 0 ( digit ‘ 2 ) 𝑎 )  ∈  ℂ ) | 
						
							| 35 |  | 1cnd | ⊢ ( 𝑎  ∈  ℕ0  →  1  ∈  ℂ ) | 
						
							| 36 | 34 35 | mulcld | ⊢ ( 𝑎  ∈  ℕ0  →  ( ( 0 ( digit ‘ 2 ) 𝑎 )  ·  1 )  ∈  ℂ ) | 
						
							| 37 | 27 36 | jca | ⊢ ( 𝑎  ∈  ℕ0  →  ( 0  ∈  ℂ  ∧  ( ( 0 ( digit ‘ 2 ) 𝑎 )  ·  1 )  ∈  ℂ ) ) | 
						
							| 38 | 37 | adantr | ⊢ ( ( 𝑎  ∈  ℕ0  ∧  ( #b ‘ 𝑎 )  =  1 )  →  ( 0  ∈  ℂ  ∧  ( ( 0 ( digit ‘ 2 ) 𝑎 )  ·  1 )  ∈  ℂ ) ) | 
						
							| 39 |  | oveq1 | ⊢ ( 𝑘  =  0  →  ( 𝑘 ( digit ‘ 2 ) 𝑎 )  =  ( 0 ( digit ‘ 2 ) 𝑎 ) ) | 
						
							| 40 |  | oveq2 | ⊢ ( 𝑘  =  0  →  ( 2 ↑ 𝑘 )  =  ( 2 ↑ 0 ) ) | 
						
							| 41 |  | 2cn | ⊢ 2  ∈  ℂ | 
						
							| 42 |  | exp0 | ⊢ ( 2  ∈  ℂ  →  ( 2 ↑ 0 )  =  1 ) | 
						
							| 43 | 41 42 | ax-mp | ⊢ ( 2 ↑ 0 )  =  1 | 
						
							| 44 | 40 43 | eqtrdi | ⊢ ( 𝑘  =  0  →  ( 2 ↑ 𝑘 )  =  1 ) | 
						
							| 45 | 39 44 | oveq12d | ⊢ ( 𝑘  =  0  →  ( ( 𝑘 ( digit ‘ 2 ) 𝑎 )  ·  ( 2 ↑ 𝑘 ) )  =  ( ( 0 ( digit ‘ 2 ) 𝑎 )  ·  1 ) ) | 
						
							| 46 | 45 | sumsn | ⊢ ( ( 0  ∈  ℂ  ∧  ( ( 0 ( digit ‘ 2 ) 𝑎 )  ·  1 )  ∈  ℂ )  →  Σ 𝑘  ∈  { 0 } ( ( 𝑘 ( digit ‘ 2 ) 𝑎 )  ·  ( 2 ↑ 𝑘 ) )  =  ( ( 0 ( digit ‘ 2 ) 𝑎 )  ·  1 ) ) | 
						
							| 47 | 38 46 | syl | ⊢ ( ( 𝑎  ∈  ℕ0  ∧  ( #b ‘ 𝑎 )  =  1 )  →  Σ 𝑘  ∈  { 0 } ( ( 𝑘 ( digit ‘ 2 ) 𝑎 )  ·  ( 2 ↑ 𝑘 ) )  =  ( ( 0 ( digit ‘ 2 ) 𝑎 )  ·  1 ) ) | 
						
							| 48 | 34 | adantr | ⊢ ( ( 𝑎  ∈  ℕ0  ∧  ( #b ‘ 𝑎 )  =  1 )  →  ( 0 ( digit ‘ 2 ) 𝑎 )  ∈  ℂ ) | 
						
							| 49 | 48 | mulridd | ⊢ ( ( 𝑎  ∈  ℕ0  ∧  ( #b ‘ 𝑎 )  =  1 )  →  ( ( 0 ( digit ‘ 2 ) 𝑎 )  ·  1 )  =  ( 0 ( digit ‘ 2 ) 𝑎 ) ) | 
						
							| 50 |  | blen1b | ⊢ ( 𝑎  ∈  ℕ0  →  ( ( #b ‘ 𝑎 )  =  1  ↔  ( 𝑎  =  0  ∨  𝑎  =  1 ) ) ) | 
						
							| 51 | 50 | biimpa | ⊢ ( ( 𝑎  ∈  ℕ0  ∧  ( #b ‘ 𝑎 )  =  1 )  →  ( 𝑎  =  0  ∨  𝑎  =  1 ) ) | 
						
							| 52 |  | vex | ⊢ 𝑎  ∈  V | 
						
							| 53 | 52 | elpr | ⊢ ( 𝑎  ∈  { 0 ,  1 }  ↔  ( 𝑎  =  0  ∨  𝑎  =  1 ) ) | 
						
							| 54 | 51 53 | sylibr | ⊢ ( ( 𝑎  ∈  ℕ0  ∧  ( #b ‘ 𝑎 )  =  1 )  →  𝑎  ∈  { 0 ,  1 } ) | 
						
							| 55 |  | 0dig2pr01 | ⊢ ( 𝑎  ∈  { 0 ,  1 }  →  ( 0 ( digit ‘ 2 ) 𝑎 )  =  𝑎 ) | 
						
							| 56 | 54 55 | syl | ⊢ ( ( 𝑎  ∈  ℕ0  ∧  ( #b ‘ 𝑎 )  =  1 )  →  ( 0 ( digit ‘ 2 ) 𝑎 )  =  𝑎 ) | 
						
							| 57 | 47 49 56 | 3eqtrrd | ⊢ ( ( 𝑎  ∈  ℕ0  ∧  ( #b ‘ 𝑎 )  =  1 )  →  𝑎  =  Σ 𝑘  ∈  { 0 } ( ( 𝑘 ( digit ‘ 2 ) 𝑎 )  ·  ( 2 ↑ 𝑘 ) ) ) | 
						
							| 58 | 57 | ex | ⊢ ( 𝑎  ∈  ℕ0  →  ( ( #b ‘ 𝑎 )  =  1  →  𝑎  =  Σ 𝑘  ∈  { 0 } ( ( 𝑘 ( digit ‘ 2 ) 𝑎 )  ·  ( 2 ↑ 𝑘 ) ) ) ) | 
						
							| 59 | 58 | rgen | ⊢ ∀ 𝑎  ∈  ℕ0 ( ( #b ‘ 𝑎 )  =  1  →  𝑎  =  Σ 𝑘  ∈  { 0 } ( ( 𝑘 ( digit ‘ 2 ) 𝑎 )  ·  ( 2 ↑ 𝑘 ) ) ) | 
						
							| 60 |  | nn0sumshdiglem1 | ⊢ ( 𝑦  ∈  ℕ  →  ( ∀ 𝑎  ∈  ℕ0 ( ( #b ‘ 𝑎 )  =  𝑦  →  𝑎  =  Σ 𝑘  ∈  ( 0 ..^ 𝑦 ) ( ( 𝑘 ( digit ‘ 2 ) 𝑎 )  ·  ( 2 ↑ 𝑘 ) ) )  →  ∀ 𝑎  ∈  ℕ0 ( ( #b ‘ 𝑎 )  =  ( 𝑦  +  1 )  →  𝑎  =  Σ 𝑘  ∈  ( 0 ..^ ( 𝑦  +  1 ) ) ( ( 𝑘 ( digit ‘ 2 ) 𝑎 )  ·  ( 2 ↑ 𝑘 ) ) ) ) ) | 
						
							| 61 | 8 14 20 26 59 60 | nnind | ⊢ ( 𝐿  ∈  ℕ  →  ∀ 𝑎  ∈  ℕ0 ( ( #b ‘ 𝑎 )  =  𝐿  →  𝑎  =  Σ 𝑘  ∈  ( 0 ..^ 𝐿 ) ( ( 𝑘 ( digit ‘ 2 ) 𝑎 )  ·  ( 2 ↑ 𝑘 ) ) ) ) |