| Step | Hyp | Ref | Expression | 
						
							| 1 |  | wfrlem6OLD.1 | ⊢ 𝐹  =  wrecs ( 𝑅 ,  𝐴 ,  𝐺 ) | 
						
							| 2 |  | dfwrecsOLD | ⊢ wrecs ( 𝑅 ,  𝐴 ,  𝐺 )  =  ∪  { 𝑓  ∣  ∃ 𝑥 ( 𝑓  Fn  𝑥  ∧  ( 𝑥  ⊆  𝐴  ∧  ∀ 𝑦  ∈  𝑥 Pred ( 𝑅 ,  𝐴 ,  𝑦 )  ⊆  𝑥 )  ∧  ∀ 𝑦  ∈  𝑥 ( 𝑓 ‘ 𝑦 )  =  ( 𝐺 ‘ ( 𝑓  ↾  Pred ( 𝑅 ,  𝐴 ,  𝑦 ) ) ) ) } | 
						
							| 3 | 1 2 | eqtri | ⊢ 𝐹  =  ∪  { 𝑓  ∣  ∃ 𝑥 ( 𝑓  Fn  𝑥  ∧  ( 𝑥  ⊆  𝐴  ∧  ∀ 𝑦  ∈  𝑥 Pred ( 𝑅 ,  𝐴 ,  𝑦 )  ⊆  𝑥 )  ∧  ∀ 𝑦  ∈  𝑥 ( 𝑓 ‘ 𝑦 )  =  ( 𝐺 ‘ ( 𝑓  ↾  Pred ( 𝑅 ,  𝐴 ,  𝑦 ) ) ) ) } | 
						
							| 4 | 3 | dmeqi | ⊢ dom  𝐹  =  dom  ∪  { 𝑓  ∣  ∃ 𝑥 ( 𝑓  Fn  𝑥  ∧  ( 𝑥  ⊆  𝐴  ∧  ∀ 𝑦  ∈  𝑥 Pred ( 𝑅 ,  𝐴 ,  𝑦 )  ⊆  𝑥 )  ∧  ∀ 𝑦  ∈  𝑥 ( 𝑓 ‘ 𝑦 )  =  ( 𝐺 ‘ ( 𝑓  ↾  Pred ( 𝑅 ,  𝐴 ,  𝑦 ) ) ) ) } | 
						
							| 5 |  | dmuni | ⊢ dom  ∪  { 𝑓  ∣  ∃ 𝑥 ( 𝑓  Fn  𝑥  ∧  ( 𝑥  ⊆  𝐴  ∧  ∀ 𝑦  ∈  𝑥 Pred ( 𝑅 ,  𝐴 ,  𝑦 )  ⊆  𝑥 )  ∧  ∀ 𝑦  ∈  𝑥 ( 𝑓 ‘ 𝑦 )  =  ( 𝐺 ‘ ( 𝑓  ↾  Pred ( 𝑅 ,  𝐴 ,  𝑦 ) ) ) ) }  =  ∪  𝑔  ∈  { 𝑓  ∣  ∃ 𝑥 ( 𝑓  Fn  𝑥  ∧  ( 𝑥  ⊆  𝐴  ∧  ∀ 𝑦  ∈  𝑥 Pred ( 𝑅 ,  𝐴 ,  𝑦 )  ⊆  𝑥 )  ∧  ∀ 𝑦  ∈  𝑥 ( 𝑓 ‘ 𝑦 )  =  ( 𝐺 ‘ ( 𝑓  ↾  Pred ( 𝑅 ,  𝐴 ,  𝑦 ) ) ) ) } dom  𝑔 | 
						
							| 6 | 4 5 | eqtri | ⊢ dom  𝐹  =  ∪  𝑔  ∈  { 𝑓  ∣  ∃ 𝑥 ( 𝑓  Fn  𝑥  ∧  ( 𝑥  ⊆  𝐴  ∧  ∀ 𝑦  ∈  𝑥 Pred ( 𝑅 ,  𝐴 ,  𝑦 )  ⊆  𝑥 )  ∧  ∀ 𝑦  ∈  𝑥 ( 𝑓 ‘ 𝑦 )  =  ( 𝐺 ‘ ( 𝑓  ↾  Pred ( 𝑅 ,  𝐴 ,  𝑦 ) ) ) ) } dom  𝑔 | 
						
							| 7 |  | iunss | ⊢ ( ∪  𝑔  ∈  { 𝑓  ∣  ∃ 𝑥 ( 𝑓  Fn  𝑥  ∧  ( 𝑥  ⊆  𝐴  ∧  ∀ 𝑦  ∈  𝑥 Pred ( 𝑅 ,  𝐴 ,  𝑦 )  ⊆  𝑥 )  ∧  ∀ 𝑦  ∈  𝑥 ( 𝑓 ‘ 𝑦 )  =  ( 𝐺 ‘ ( 𝑓  ↾  Pred ( 𝑅 ,  𝐴 ,  𝑦 ) ) ) ) } dom  𝑔  ⊆  𝐴  ↔  ∀ 𝑔  ∈  { 𝑓  ∣  ∃ 𝑥 ( 𝑓  Fn  𝑥  ∧  ( 𝑥  ⊆  𝐴  ∧  ∀ 𝑦  ∈  𝑥 Pred ( 𝑅 ,  𝐴 ,  𝑦 )  ⊆  𝑥 )  ∧  ∀ 𝑦  ∈  𝑥 ( 𝑓 ‘ 𝑦 )  =  ( 𝐺 ‘ ( 𝑓  ↾  Pred ( 𝑅 ,  𝐴 ,  𝑦 ) ) ) ) } dom  𝑔  ⊆  𝐴 ) | 
						
							| 8 |  | eqid | ⊢ { 𝑓  ∣  ∃ 𝑥 ( 𝑓  Fn  𝑥  ∧  ( 𝑥  ⊆  𝐴  ∧  ∀ 𝑦  ∈  𝑥 Pred ( 𝑅 ,  𝐴 ,  𝑦 )  ⊆  𝑥 )  ∧  ∀ 𝑦  ∈  𝑥 ( 𝑓 ‘ 𝑦 )  =  ( 𝐺 ‘ ( 𝑓  ↾  Pred ( 𝑅 ,  𝐴 ,  𝑦 ) ) ) ) }  =  { 𝑓  ∣  ∃ 𝑥 ( 𝑓  Fn  𝑥  ∧  ( 𝑥  ⊆  𝐴  ∧  ∀ 𝑦  ∈  𝑥 Pred ( 𝑅 ,  𝐴 ,  𝑦 )  ⊆  𝑥 )  ∧  ∀ 𝑦  ∈  𝑥 ( 𝑓 ‘ 𝑦 )  =  ( 𝐺 ‘ ( 𝑓  ↾  Pred ( 𝑅 ,  𝐴 ,  𝑦 ) ) ) ) } | 
						
							| 9 | 8 | wfrlem3OLD | ⊢ ( 𝑔  ∈  { 𝑓  ∣  ∃ 𝑥 ( 𝑓  Fn  𝑥  ∧  ( 𝑥  ⊆  𝐴  ∧  ∀ 𝑦  ∈  𝑥 Pred ( 𝑅 ,  𝐴 ,  𝑦 )  ⊆  𝑥 )  ∧  ∀ 𝑦  ∈  𝑥 ( 𝑓 ‘ 𝑦 )  =  ( 𝐺 ‘ ( 𝑓  ↾  Pred ( 𝑅 ,  𝐴 ,  𝑦 ) ) ) ) }  →  dom  𝑔  ⊆  𝐴 ) | 
						
							| 10 | 7 9 | mprgbir | ⊢ ∪  𝑔  ∈  { 𝑓  ∣  ∃ 𝑥 ( 𝑓  Fn  𝑥  ∧  ( 𝑥  ⊆  𝐴  ∧  ∀ 𝑦  ∈  𝑥 Pred ( 𝑅 ,  𝐴 ,  𝑦 )  ⊆  𝑥 )  ∧  ∀ 𝑦  ∈  𝑥 ( 𝑓 ‘ 𝑦 )  =  ( 𝐺 ‘ ( 𝑓  ↾  Pred ( 𝑅 ,  𝐴 ,  𝑦 ) ) ) ) } dom  𝑔  ⊆  𝐴 | 
						
							| 11 | 6 10 | eqsstri | ⊢ dom  𝐹  ⊆  𝐴 |