| Step | Hyp | Ref | Expression | 
						
							| 1 |  | wfrlem6OLD.1 | ⊢ 𝐹  =  wrecs ( 𝑅 ,  𝐴 ,  𝐺 ) | 
						
							| 2 |  | reluni | ⊢ ( Rel  ∪  { 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 ) ) ) ) } Rel  𝑔 ) | 
						
							| 3 |  | 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 ) ) ) ) } | 
						
							| 4 | 3 | wfrlem2OLD | ⊢ ( 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 ) ) ) ) }  →  Fun  𝑔 ) | 
						
							| 5 |  | funrel | ⊢ ( Fun  𝑔  →  Rel  𝑔 ) | 
						
							| 6 | 4 5 | syl | ⊢ ( 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 ) ) ) ) }  →  Rel  𝑔 ) | 
						
							| 7 | 2 6 | mprgbir | ⊢ Rel  ∪  { 𝑓  ∣  ∃ 𝑥 ( 𝑓  Fn  𝑥  ∧  ( 𝑥  ⊆  𝐴  ∧  ∀ 𝑦  ∈  𝑥 Pred ( 𝑅 ,  𝐴 ,  𝑦 )  ⊆  𝑥 )  ∧  ∀ 𝑦  ∈  𝑥 ( 𝑓 ‘ 𝑦 )  =  ( 𝐺 ‘ ( 𝑓  ↾  Pred ( 𝑅 ,  𝐴 ,  𝑦 ) ) ) ) } | 
						
							| 8 |  | 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 ) ) ) ) } | 
						
							| 9 | 1 8 | 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 ) ) ) ) } | 
						
							| 10 | 9 | releqi | ⊢ ( Rel  𝐹  ↔  Rel  ∪  { 𝑓  ∣  ∃ 𝑥 ( 𝑓  Fn  𝑥  ∧  ( 𝑥  ⊆  𝐴  ∧  ∀ 𝑦  ∈  𝑥 Pred ( 𝑅 ,  𝐴 ,  𝑦 )  ⊆  𝑥 )  ∧  ∀ 𝑦  ∈  𝑥 ( 𝑓 ‘ 𝑦 )  =  ( 𝐺 ‘ ( 𝑓  ↾  Pred ( 𝑅 ,  𝐴 ,  𝑦 ) ) ) ) } ) | 
						
							| 11 | 7 10 | mpbir | ⊢ Rel  𝐹 |