| Step | Hyp | Ref | Expression | 
						
							| 1 |  | ackbij.f | ⊢ 𝐹  =  ( 𝑥  ∈  ( 𝒫  ω  ∩  Fin )  ↦  ( card ‘ ∪  𝑦  ∈  𝑥 ( { 𝑦 }  ×  𝒫  𝑦 ) ) ) | 
						
							| 2 | 1 | ackbij1lem10 | ⊢ 𝐹 : ( 𝒫  ω  ∩  Fin ) ⟶ ω | 
						
							| 3 | 1 | ackbij1lem11 | ⊢ ( ( 𝐵  ∈  ( 𝒫  ω  ∩  Fin )  ∧  𝐴  ⊆  𝐵 )  →  𝐴  ∈  ( 𝒫  ω  ∩  Fin ) ) | 
						
							| 4 |  | ffvelcdm | ⊢ ( ( 𝐹 : ( 𝒫  ω  ∩  Fin ) ⟶ ω  ∧  𝐴  ∈  ( 𝒫  ω  ∩  Fin ) )  →  ( 𝐹 ‘ 𝐴 )  ∈  ω ) | 
						
							| 5 | 2 3 4 | sylancr | ⊢ ( ( 𝐵  ∈  ( 𝒫  ω  ∩  Fin )  ∧  𝐴  ⊆  𝐵 )  →  ( 𝐹 ‘ 𝐴 )  ∈  ω ) | 
						
							| 6 |  | difssd | ⊢ ( ( 𝐵  ∈  ( 𝒫  ω  ∩  Fin )  ∧  𝐴  ⊆  𝐵 )  →  ( 𝐵  ∖  𝐴 )  ⊆  𝐵 ) | 
						
							| 7 | 1 | ackbij1lem11 | ⊢ ( ( 𝐵  ∈  ( 𝒫  ω  ∩  Fin )  ∧  ( 𝐵  ∖  𝐴 )  ⊆  𝐵 )  →  ( 𝐵  ∖  𝐴 )  ∈  ( 𝒫  ω  ∩  Fin ) ) | 
						
							| 8 | 6 7 | syldan | ⊢ ( ( 𝐵  ∈  ( 𝒫  ω  ∩  Fin )  ∧  𝐴  ⊆  𝐵 )  →  ( 𝐵  ∖  𝐴 )  ∈  ( 𝒫  ω  ∩  Fin ) ) | 
						
							| 9 |  | ffvelcdm | ⊢ ( ( 𝐹 : ( 𝒫  ω  ∩  Fin ) ⟶ ω  ∧  ( 𝐵  ∖  𝐴 )  ∈  ( 𝒫  ω  ∩  Fin ) )  →  ( 𝐹 ‘ ( 𝐵  ∖  𝐴 ) )  ∈  ω ) | 
						
							| 10 | 2 8 9 | sylancr | ⊢ ( ( 𝐵  ∈  ( 𝒫  ω  ∩  Fin )  ∧  𝐴  ⊆  𝐵 )  →  ( 𝐹 ‘ ( 𝐵  ∖  𝐴 ) )  ∈  ω ) | 
						
							| 11 |  | nnaword1 | ⊢ ( ( ( 𝐹 ‘ 𝐴 )  ∈  ω  ∧  ( 𝐹 ‘ ( 𝐵  ∖  𝐴 ) )  ∈  ω )  →  ( 𝐹 ‘ 𝐴 )  ⊆  ( ( 𝐹 ‘ 𝐴 )  +o  ( 𝐹 ‘ ( 𝐵  ∖  𝐴 ) ) ) ) | 
						
							| 12 | 5 10 11 | syl2anc | ⊢ ( ( 𝐵  ∈  ( 𝒫  ω  ∩  Fin )  ∧  𝐴  ⊆  𝐵 )  →  ( 𝐹 ‘ 𝐴 )  ⊆  ( ( 𝐹 ‘ 𝐴 )  +o  ( 𝐹 ‘ ( 𝐵  ∖  𝐴 ) ) ) ) | 
						
							| 13 |  | disjdif | ⊢ ( 𝐴  ∩  ( 𝐵  ∖  𝐴 ) )  =  ∅ | 
						
							| 14 | 13 | a1i | ⊢ ( ( 𝐵  ∈  ( 𝒫  ω  ∩  Fin )  ∧  𝐴  ⊆  𝐵 )  →  ( 𝐴  ∩  ( 𝐵  ∖  𝐴 ) )  =  ∅ ) | 
						
							| 15 | 1 | ackbij1lem9 | ⊢ ( ( 𝐴  ∈  ( 𝒫  ω  ∩  Fin )  ∧  ( 𝐵  ∖  𝐴 )  ∈  ( 𝒫  ω  ∩  Fin )  ∧  ( 𝐴  ∩  ( 𝐵  ∖  𝐴 ) )  =  ∅ )  →  ( 𝐹 ‘ ( 𝐴  ∪  ( 𝐵  ∖  𝐴 ) ) )  =  ( ( 𝐹 ‘ 𝐴 )  +o  ( 𝐹 ‘ ( 𝐵  ∖  𝐴 ) ) ) ) | 
						
							| 16 | 3 8 14 15 | syl3anc | ⊢ ( ( 𝐵  ∈  ( 𝒫  ω  ∩  Fin )  ∧  𝐴  ⊆  𝐵 )  →  ( 𝐹 ‘ ( 𝐴  ∪  ( 𝐵  ∖  𝐴 ) ) )  =  ( ( 𝐹 ‘ 𝐴 )  +o  ( 𝐹 ‘ ( 𝐵  ∖  𝐴 ) ) ) ) | 
						
							| 17 |  | undif | ⊢ ( 𝐴  ⊆  𝐵  ↔  ( 𝐴  ∪  ( 𝐵  ∖  𝐴 ) )  =  𝐵 ) | 
						
							| 18 | 17 | biimpi | ⊢ ( 𝐴  ⊆  𝐵  →  ( 𝐴  ∪  ( 𝐵  ∖  𝐴 ) )  =  𝐵 ) | 
						
							| 19 | 18 | adantl | ⊢ ( ( 𝐵  ∈  ( 𝒫  ω  ∩  Fin )  ∧  𝐴  ⊆  𝐵 )  →  ( 𝐴  ∪  ( 𝐵  ∖  𝐴 ) )  =  𝐵 ) | 
						
							| 20 | 19 | fveq2d | ⊢ ( ( 𝐵  ∈  ( 𝒫  ω  ∩  Fin )  ∧  𝐴  ⊆  𝐵 )  →  ( 𝐹 ‘ ( 𝐴  ∪  ( 𝐵  ∖  𝐴 ) ) )  =  ( 𝐹 ‘ 𝐵 ) ) | 
						
							| 21 | 16 20 | eqtr3d | ⊢ ( ( 𝐵  ∈  ( 𝒫  ω  ∩  Fin )  ∧  𝐴  ⊆  𝐵 )  →  ( ( 𝐹 ‘ 𝐴 )  +o  ( 𝐹 ‘ ( 𝐵  ∖  𝐴 ) ) )  =  ( 𝐹 ‘ 𝐵 ) ) | 
						
							| 22 | 12 21 | sseqtrd | ⊢ ( ( 𝐵  ∈  ( 𝒫  ω  ∩  Fin )  ∧  𝐴  ⊆  𝐵 )  →  ( 𝐹 ‘ 𝐴 )  ⊆  ( 𝐹 ‘ 𝐵 ) ) |