| Step | 
						Hyp | 
						Ref | 
						Expression | 
					
						
							| 1 | 
							
								
							 | 
							ballotth.m | 
							⊢ 𝑀  ∈  ℕ  | 
						
						
							| 2 | 
							
								
							 | 
							ballotth.n | 
							⊢ 𝑁  ∈  ℕ  | 
						
						
							| 3 | 
							
								
							 | 
							ballotth.o | 
							⊢ 𝑂  =  { 𝑐  ∈  𝒫  ( 1 ... ( 𝑀  +  𝑁 ) )  ∣  ( ♯ ‘ 𝑐 )  =  𝑀 }  | 
						
						
							| 4 | 
							
								
							 | 
							ballotth.p | 
							⊢ 𝑃  =  ( 𝑥  ∈  𝒫  𝑂  ↦  ( ( ♯ ‘ 𝑥 )  /  ( ♯ ‘ 𝑂 ) ) )  | 
						
						
							| 5 | 
							
								
							 | 
							ballotth.f | 
							⊢ 𝐹  =  ( 𝑐  ∈  𝑂  ↦  ( 𝑖  ∈  ℤ  ↦  ( ( ♯ ‘ ( ( 1 ... 𝑖 )  ∩  𝑐 ) )  −  ( ♯ ‘ ( ( 1 ... 𝑖 )  ∖  𝑐 ) ) ) ) )  | 
						
						
							| 6 | 
							
								
							 | 
							ballotlemfval.c | 
							⊢ ( 𝜑  →  𝐶  ∈  𝑂 )  | 
						
						
							| 7 | 
							
								
							 | 
							ballotlemfval.j | 
							⊢ ( 𝜑  →  𝐽  ∈  ℤ )  | 
						
						
							| 8 | 
							
								1 2 3 4 5 6 7
							 | 
							ballotlemfval | 
							⊢ ( 𝜑  →  ( ( 𝐹 ‘ 𝐶 ) ‘ 𝐽 )  =  ( ( ♯ ‘ ( ( 1 ... 𝐽 )  ∩  𝐶 ) )  −  ( ♯ ‘ ( ( 1 ... 𝐽 )  ∖  𝐶 ) ) ) )  | 
						
						
							| 9 | 
							
								
							 | 
							fzfi | 
							⊢ ( 1 ... 𝐽 )  ∈  Fin  | 
						
						
							| 10 | 
							
								
							 | 
							inss1 | 
							⊢ ( ( 1 ... 𝐽 )  ∩  𝐶 )  ⊆  ( 1 ... 𝐽 )  | 
						
						
							| 11 | 
							
								
							 | 
							ssfi | 
							⊢ ( ( ( 1 ... 𝐽 )  ∈  Fin  ∧  ( ( 1 ... 𝐽 )  ∩  𝐶 )  ⊆  ( 1 ... 𝐽 ) )  →  ( ( 1 ... 𝐽 )  ∩  𝐶 )  ∈  Fin )  | 
						
						
							| 12 | 
							
								9 10 11
							 | 
							mp2an | 
							⊢ ( ( 1 ... 𝐽 )  ∩  𝐶 )  ∈  Fin  | 
						
						
							| 13 | 
							
								
							 | 
							hashcl | 
							⊢ ( ( ( 1 ... 𝐽 )  ∩  𝐶 )  ∈  Fin  →  ( ♯ ‘ ( ( 1 ... 𝐽 )  ∩  𝐶 ) )  ∈  ℕ0 )  | 
						
						
							| 14 | 
							
								12 13
							 | 
							ax-mp | 
							⊢ ( ♯ ‘ ( ( 1 ... 𝐽 )  ∩  𝐶 ) )  ∈  ℕ0  | 
						
						
							| 15 | 
							
								14
							 | 
							nn0zi | 
							⊢ ( ♯ ‘ ( ( 1 ... 𝐽 )  ∩  𝐶 ) )  ∈  ℤ  | 
						
						
							| 16 | 
							
								
							 | 
							difss | 
							⊢ ( ( 1 ... 𝐽 )  ∖  𝐶 )  ⊆  ( 1 ... 𝐽 )  | 
						
						
							| 17 | 
							
								
							 | 
							ssfi | 
							⊢ ( ( ( 1 ... 𝐽 )  ∈  Fin  ∧  ( ( 1 ... 𝐽 )  ∖  𝐶 )  ⊆  ( 1 ... 𝐽 ) )  →  ( ( 1 ... 𝐽 )  ∖  𝐶 )  ∈  Fin )  | 
						
						
							| 18 | 
							
								9 16 17
							 | 
							mp2an | 
							⊢ ( ( 1 ... 𝐽 )  ∖  𝐶 )  ∈  Fin  | 
						
						
							| 19 | 
							
								
							 | 
							hashcl | 
							⊢ ( ( ( 1 ... 𝐽 )  ∖  𝐶 )  ∈  Fin  →  ( ♯ ‘ ( ( 1 ... 𝐽 )  ∖  𝐶 ) )  ∈  ℕ0 )  | 
						
						
							| 20 | 
							
								18 19
							 | 
							ax-mp | 
							⊢ ( ♯ ‘ ( ( 1 ... 𝐽 )  ∖  𝐶 ) )  ∈  ℕ0  | 
						
						
							| 21 | 
							
								20
							 | 
							nn0zi | 
							⊢ ( ♯ ‘ ( ( 1 ... 𝐽 )  ∖  𝐶 ) )  ∈  ℤ  | 
						
						
							| 22 | 
							
								
							 | 
							zsubcl | 
							⊢ ( ( ( ♯ ‘ ( ( 1 ... 𝐽 )  ∩  𝐶 ) )  ∈  ℤ  ∧  ( ♯ ‘ ( ( 1 ... 𝐽 )  ∖  𝐶 ) )  ∈  ℤ )  →  ( ( ♯ ‘ ( ( 1 ... 𝐽 )  ∩  𝐶 ) )  −  ( ♯ ‘ ( ( 1 ... 𝐽 )  ∖  𝐶 ) ) )  ∈  ℤ )  | 
						
						
							| 23 | 
							
								15 21 22
							 | 
							mp2an | 
							⊢ ( ( ♯ ‘ ( ( 1 ... 𝐽 )  ∩  𝐶 ) )  −  ( ♯ ‘ ( ( 1 ... 𝐽 )  ∖  𝐶 ) ) )  ∈  ℤ  | 
						
						
							| 24 | 
							
								8 23
							 | 
							eqeltrdi | 
							⊢ ( 𝜑  →  ( ( 𝐹 ‘ 𝐶 ) ‘ 𝐽 )  ∈  ℤ )  |