| Step | Hyp | Ref | Expression | 
						
							| 1 |  | coe1mul2lem2.h | ⊢ 𝐻  =  { 𝑑  ∈  ( ℕ0  ↑m  1o )  ∣  𝑑  ∘r   ≤  ( 1o  ×  { 𝑘 } ) } | 
						
							| 2 |  | df1o2 | ⊢ 1o  =  { ∅ } | 
						
							| 3 |  | nn0ex | ⊢ ℕ0  ∈  V | 
						
							| 4 |  | 0ex | ⊢ ∅  ∈  V | 
						
							| 5 |  | eqid | ⊢ ( 𝑐  ∈  ( ℕ0  ↑m  1o )  ↦  ( 𝑐 ‘ ∅ ) )  =  ( 𝑐  ∈  ( ℕ0  ↑m  1o )  ↦  ( 𝑐 ‘ ∅ ) ) | 
						
							| 6 | 2 3 4 5 | mapsnf1o2 | ⊢ ( 𝑐  ∈  ( ℕ0  ↑m  1o )  ↦  ( 𝑐 ‘ ∅ ) ) : ( ℕ0  ↑m  1o ) –1-1-onto→ ℕ0 | 
						
							| 7 |  | f1of1 | ⊢ ( ( 𝑐  ∈  ( ℕ0  ↑m  1o )  ↦  ( 𝑐 ‘ ∅ ) ) : ( ℕ0  ↑m  1o ) –1-1-onto→ ℕ0  →  ( 𝑐  ∈  ( ℕ0  ↑m  1o )  ↦  ( 𝑐 ‘ ∅ ) ) : ( ℕ0  ↑m  1o ) –1-1→ ℕ0 ) | 
						
							| 8 | 6 7 | ax-mp | ⊢ ( 𝑐  ∈  ( ℕ0  ↑m  1o )  ↦  ( 𝑐 ‘ ∅ ) ) : ( ℕ0  ↑m  1o ) –1-1→ ℕ0 | 
						
							| 9 | 1 | ssrab3 | ⊢ 𝐻  ⊆  ( ℕ0  ↑m  1o ) | 
						
							| 10 | 9 | a1i | ⊢ ( 𝑘  ∈  ℕ0  →  𝐻  ⊆  ( ℕ0  ↑m  1o ) ) | 
						
							| 11 |  | f1ores | ⊢ ( ( ( 𝑐  ∈  ( ℕ0  ↑m  1o )  ↦  ( 𝑐 ‘ ∅ ) ) : ( ℕ0  ↑m  1o ) –1-1→ ℕ0  ∧  𝐻  ⊆  ( ℕ0  ↑m  1o ) )  →  ( ( 𝑐  ∈  ( ℕ0  ↑m  1o )  ↦  ( 𝑐 ‘ ∅ ) )  ↾  𝐻 ) : 𝐻 –1-1-onto→ ( ( 𝑐  ∈  ( ℕ0  ↑m  1o )  ↦  ( 𝑐 ‘ ∅ ) )  “  𝐻 ) ) | 
						
							| 12 | 8 10 11 | sylancr | ⊢ ( 𝑘  ∈  ℕ0  →  ( ( 𝑐  ∈  ( ℕ0  ↑m  1o )  ↦  ( 𝑐 ‘ ∅ ) )  ↾  𝐻 ) : 𝐻 –1-1-onto→ ( ( 𝑐  ∈  ( ℕ0  ↑m  1o )  ↦  ( 𝑐 ‘ ∅ ) )  “  𝐻 ) ) | 
						
							| 13 |  | coe1mul2lem1 | ⊢ ( ( 𝑘  ∈  ℕ0  ∧  𝑑  ∈  ( ℕ0  ↑m  1o ) )  →  ( 𝑑  ∘r   ≤  ( 1o  ×  { 𝑘 } )  ↔  ( 𝑑 ‘ ∅ )  ∈  ( 0 ... 𝑘 ) ) ) | 
						
							| 14 | 13 | rabbidva | ⊢ ( 𝑘  ∈  ℕ0  →  { 𝑑  ∈  ( ℕ0  ↑m  1o )  ∣  𝑑  ∘r   ≤  ( 1o  ×  { 𝑘 } ) }  =  { 𝑑  ∈  ( ℕ0  ↑m  1o )  ∣  ( 𝑑 ‘ ∅ )  ∈  ( 0 ... 𝑘 ) } ) | 
						
							| 15 |  | fveq1 | ⊢ ( 𝑐  =  𝑑  →  ( 𝑐 ‘ ∅ )  =  ( 𝑑 ‘ ∅ ) ) | 
						
							| 16 | 15 | eleq1d | ⊢ ( 𝑐  =  𝑑  →  ( ( 𝑐 ‘ ∅ )  ∈  ( 0 ... 𝑘 )  ↔  ( 𝑑 ‘ ∅ )  ∈  ( 0 ... 𝑘 ) ) ) | 
						
							| 17 | 16 | cbvrabv | ⊢ { 𝑐  ∈  ( ℕ0  ↑m  1o )  ∣  ( 𝑐 ‘ ∅ )  ∈  ( 0 ... 𝑘 ) }  =  { 𝑑  ∈  ( ℕ0  ↑m  1o )  ∣  ( 𝑑 ‘ ∅ )  ∈  ( 0 ... 𝑘 ) } | 
						
							| 18 | 14 17 | eqtr4di | ⊢ ( 𝑘  ∈  ℕ0  →  { 𝑑  ∈  ( ℕ0  ↑m  1o )  ∣  𝑑  ∘r   ≤  ( 1o  ×  { 𝑘 } ) }  =  { 𝑐  ∈  ( ℕ0  ↑m  1o )  ∣  ( 𝑐 ‘ ∅ )  ∈  ( 0 ... 𝑘 ) } ) | 
						
							| 19 | 5 | mptpreima | ⊢ ( ◡ ( 𝑐  ∈  ( ℕ0  ↑m  1o )  ↦  ( 𝑐 ‘ ∅ ) )  “  ( 0 ... 𝑘 ) )  =  { 𝑐  ∈  ( ℕ0  ↑m  1o )  ∣  ( 𝑐 ‘ ∅ )  ∈  ( 0 ... 𝑘 ) } | 
						
							| 20 | 18 1 19 | 3eqtr4g | ⊢ ( 𝑘  ∈  ℕ0  →  𝐻  =  ( ◡ ( 𝑐  ∈  ( ℕ0  ↑m  1o )  ↦  ( 𝑐 ‘ ∅ ) )  “  ( 0 ... 𝑘 ) ) ) | 
						
							| 21 | 20 | imaeq2d | ⊢ ( 𝑘  ∈  ℕ0  →  ( ( 𝑐  ∈  ( ℕ0  ↑m  1o )  ↦  ( 𝑐 ‘ ∅ ) )  “  𝐻 )  =  ( ( 𝑐  ∈  ( ℕ0  ↑m  1o )  ↦  ( 𝑐 ‘ ∅ ) )  “  ( ◡ ( 𝑐  ∈  ( ℕ0  ↑m  1o )  ↦  ( 𝑐 ‘ ∅ ) )  “  ( 0 ... 𝑘 ) ) ) ) | 
						
							| 22 |  | f1ofo | ⊢ ( ( 𝑐  ∈  ( ℕ0  ↑m  1o )  ↦  ( 𝑐 ‘ ∅ ) ) : ( ℕ0  ↑m  1o ) –1-1-onto→ ℕ0  →  ( 𝑐  ∈  ( ℕ0  ↑m  1o )  ↦  ( 𝑐 ‘ ∅ ) ) : ( ℕ0  ↑m  1o ) –onto→ ℕ0 ) | 
						
							| 23 | 6 22 | ax-mp | ⊢ ( 𝑐  ∈  ( ℕ0  ↑m  1o )  ↦  ( 𝑐 ‘ ∅ ) ) : ( ℕ0  ↑m  1o ) –onto→ ℕ0 | 
						
							| 24 |  | fz0ssnn0 | ⊢ ( 0 ... 𝑘 )  ⊆  ℕ0 | 
						
							| 25 |  | foimacnv | ⊢ ( ( ( 𝑐  ∈  ( ℕ0  ↑m  1o )  ↦  ( 𝑐 ‘ ∅ ) ) : ( ℕ0  ↑m  1o ) –onto→ ℕ0  ∧  ( 0 ... 𝑘 )  ⊆  ℕ0 )  →  ( ( 𝑐  ∈  ( ℕ0  ↑m  1o )  ↦  ( 𝑐 ‘ ∅ ) )  “  ( ◡ ( 𝑐  ∈  ( ℕ0  ↑m  1o )  ↦  ( 𝑐 ‘ ∅ ) )  “  ( 0 ... 𝑘 ) ) )  =  ( 0 ... 𝑘 ) ) | 
						
							| 26 | 23 24 25 | mp2an | ⊢ ( ( 𝑐  ∈  ( ℕ0  ↑m  1o )  ↦  ( 𝑐 ‘ ∅ ) )  “  ( ◡ ( 𝑐  ∈  ( ℕ0  ↑m  1o )  ↦  ( 𝑐 ‘ ∅ ) )  “  ( 0 ... 𝑘 ) ) )  =  ( 0 ... 𝑘 ) | 
						
							| 27 | 21 26 | eqtrdi | ⊢ ( 𝑘  ∈  ℕ0  →  ( ( 𝑐  ∈  ( ℕ0  ↑m  1o )  ↦  ( 𝑐 ‘ ∅ ) )  “  𝐻 )  =  ( 0 ... 𝑘 ) ) | 
						
							| 28 | 27 | f1oeq3d | ⊢ ( 𝑘  ∈  ℕ0  →  ( ( ( 𝑐  ∈  ( ℕ0  ↑m  1o )  ↦  ( 𝑐 ‘ ∅ ) )  ↾  𝐻 ) : 𝐻 –1-1-onto→ ( ( 𝑐  ∈  ( ℕ0  ↑m  1o )  ↦  ( 𝑐 ‘ ∅ ) )  “  𝐻 )  ↔  ( ( 𝑐  ∈  ( ℕ0  ↑m  1o )  ↦  ( 𝑐 ‘ ∅ ) )  ↾  𝐻 ) : 𝐻 –1-1-onto→ ( 0 ... 𝑘 ) ) ) | 
						
							| 29 |  | resmpt | ⊢ ( 𝐻  ⊆  ( ℕ0  ↑m  1o )  →  ( ( 𝑐  ∈  ( ℕ0  ↑m  1o )  ↦  ( 𝑐 ‘ ∅ ) )  ↾  𝐻 )  =  ( 𝑐  ∈  𝐻  ↦  ( 𝑐 ‘ ∅ ) ) ) | 
						
							| 30 |  | f1oeq1 | ⊢ ( ( ( 𝑐  ∈  ( ℕ0  ↑m  1o )  ↦  ( 𝑐 ‘ ∅ ) )  ↾  𝐻 )  =  ( 𝑐  ∈  𝐻  ↦  ( 𝑐 ‘ ∅ ) )  →  ( ( ( 𝑐  ∈  ( ℕ0  ↑m  1o )  ↦  ( 𝑐 ‘ ∅ ) )  ↾  𝐻 ) : 𝐻 –1-1-onto→ ( 0 ... 𝑘 )  ↔  ( 𝑐  ∈  𝐻  ↦  ( 𝑐 ‘ ∅ ) ) : 𝐻 –1-1-onto→ ( 0 ... 𝑘 ) ) ) | 
						
							| 31 | 10 29 30 | 3syl | ⊢ ( 𝑘  ∈  ℕ0  →  ( ( ( 𝑐  ∈  ( ℕ0  ↑m  1o )  ↦  ( 𝑐 ‘ ∅ ) )  ↾  𝐻 ) : 𝐻 –1-1-onto→ ( 0 ... 𝑘 )  ↔  ( 𝑐  ∈  𝐻  ↦  ( 𝑐 ‘ ∅ ) ) : 𝐻 –1-1-onto→ ( 0 ... 𝑘 ) ) ) | 
						
							| 32 | 28 31 | bitrd | ⊢ ( 𝑘  ∈  ℕ0  →  ( ( ( 𝑐  ∈  ( ℕ0  ↑m  1o )  ↦  ( 𝑐 ‘ ∅ ) )  ↾  𝐻 ) : 𝐻 –1-1-onto→ ( ( 𝑐  ∈  ( ℕ0  ↑m  1o )  ↦  ( 𝑐 ‘ ∅ ) )  “  𝐻 )  ↔  ( 𝑐  ∈  𝐻  ↦  ( 𝑐 ‘ ∅ ) ) : 𝐻 –1-1-onto→ ( 0 ... 𝑘 ) ) ) | 
						
							| 33 | 12 32 | mpbid | ⊢ ( 𝑘  ∈  ℕ0  →  ( 𝑐  ∈  𝐻  ↦  ( 𝑐 ‘ ∅ ) ) : 𝐻 –1-1-onto→ ( 0 ... 𝑘 ) ) |