| Step | Hyp | Ref | Expression | 
						
							| 1 |  | issubc.h | ⊢ 𝐻  =  ( Homf  ‘ 𝐶 ) | 
						
							| 2 |  | issubc.i | ⊢  1   =  ( Id ‘ 𝐶 ) | 
						
							| 3 |  | issubc.o | ⊢  ·   =  ( comp ‘ 𝐶 ) | 
						
							| 4 |  | issubc.c | ⊢ ( 𝜑  →  𝐶  ∈  Cat ) | 
						
							| 5 |  | issubc.s | ⊢ ( 𝜑  →  𝑆  =  dom  dom  𝐽 ) | 
						
							| 6 |  | simpl | ⊢ ( ( 𝐶  ∈  Cat  ∧  𝑆  =  dom  dom  𝐽 )  →  𝐶  ∈  Cat ) | 
						
							| 7 |  | sscpwex | ⊢ { 𝑗  ∣  𝑗  ⊆cat  ( Homf  ‘ 𝑐 ) }  ∈  V | 
						
							| 8 |  | simpl | ⊢ ( ( 𝑗  ⊆cat  ( Homf  ‘ 𝑐 )  ∧  [ dom  dom  𝑗  /  𝑠 ] ∀ 𝑥  ∈  𝑠 ( ( ( Id ‘ 𝑐 ) ‘ 𝑥 )  ∈  ( 𝑥 𝑗 𝑥 )  ∧  ∀ 𝑦  ∈  𝑠 ∀ 𝑧  ∈  𝑠 ∀ 𝑓  ∈  ( 𝑥 𝑗 𝑦 ) ∀ 𝑔  ∈  ( 𝑦 𝑗 𝑧 ) ( 𝑔 ( 〈 𝑥 ,  𝑦 〉 ( comp ‘ 𝑐 ) 𝑧 ) 𝑓 )  ∈  ( 𝑥 𝑗 𝑧 ) ) )  →  𝑗  ⊆cat  ( Homf  ‘ 𝑐 ) ) | 
						
							| 9 | 8 | ss2abi | ⊢ { 𝑗  ∣  ( 𝑗  ⊆cat  ( Homf  ‘ 𝑐 )  ∧  [ dom  dom  𝑗  /  𝑠 ] ∀ 𝑥  ∈  𝑠 ( ( ( Id ‘ 𝑐 ) ‘ 𝑥 )  ∈  ( 𝑥 𝑗 𝑥 )  ∧  ∀ 𝑦  ∈  𝑠 ∀ 𝑧  ∈  𝑠 ∀ 𝑓  ∈  ( 𝑥 𝑗 𝑦 ) ∀ 𝑔  ∈  ( 𝑦 𝑗 𝑧 ) ( 𝑔 ( 〈 𝑥 ,  𝑦 〉 ( comp ‘ 𝑐 ) 𝑧 ) 𝑓 )  ∈  ( 𝑥 𝑗 𝑧 ) ) ) }  ⊆  { 𝑗  ∣  𝑗  ⊆cat  ( Homf  ‘ 𝑐 ) } | 
						
							| 10 | 7 9 | ssexi | ⊢ { 𝑗  ∣  ( 𝑗  ⊆cat  ( Homf  ‘ 𝑐 )  ∧  [ dom  dom  𝑗  /  𝑠 ] ∀ 𝑥  ∈  𝑠 ( ( ( Id ‘ 𝑐 ) ‘ 𝑥 )  ∈  ( 𝑥 𝑗 𝑥 )  ∧  ∀ 𝑦  ∈  𝑠 ∀ 𝑧  ∈  𝑠 ∀ 𝑓  ∈  ( 𝑥 𝑗 𝑦 ) ∀ 𝑔  ∈  ( 𝑦 𝑗 𝑧 ) ( 𝑔 ( 〈 𝑥 ,  𝑦 〉 ( comp ‘ 𝑐 ) 𝑧 ) 𝑓 )  ∈  ( 𝑥 𝑗 𝑧 ) ) ) }  ∈  V | 
						
							| 11 | 10 | csbex | ⊢ ⦋ 𝐶  /  𝑐 ⦌ { 𝑗  ∣  ( 𝑗  ⊆cat  ( Homf  ‘ 𝑐 )  ∧  [ dom  dom  𝑗  /  𝑠 ] ∀ 𝑥  ∈  𝑠 ( ( ( Id ‘ 𝑐 ) ‘ 𝑥 )  ∈  ( 𝑥 𝑗 𝑥 )  ∧  ∀ 𝑦  ∈  𝑠 ∀ 𝑧  ∈  𝑠 ∀ 𝑓  ∈  ( 𝑥 𝑗 𝑦 ) ∀ 𝑔  ∈  ( 𝑦 𝑗 𝑧 ) ( 𝑔 ( 〈 𝑥 ,  𝑦 〉 ( comp ‘ 𝑐 ) 𝑧 ) 𝑓 )  ∈  ( 𝑥 𝑗 𝑧 ) ) ) }  ∈  V | 
						
							| 12 | 11 | a1i | ⊢ ( ( 𝐶  ∈  Cat  ∧  𝑆  =  dom  dom  𝐽 )  →  ⦋ 𝐶  /  𝑐 ⦌ { 𝑗  ∣  ( 𝑗  ⊆cat  ( Homf  ‘ 𝑐 )  ∧  [ dom  dom  𝑗  /  𝑠 ] ∀ 𝑥  ∈  𝑠 ( ( ( Id ‘ 𝑐 ) ‘ 𝑥 )  ∈  ( 𝑥 𝑗 𝑥 )  ∧  ∀ 𝑦  ∈  𝑠 ∀ 𝑧  ∈  𝑠 ∀ 𝑓  ∈  ( 𝑥 𝑗 𝑦 ) ∀ 𝑔  ∈  ( 𝑦 𝑗 𝑧 ) ( 𝑔 ( 〈 𝑥 ,  𝑦 〉 ( comp ‘ 𝑐 ) 𝑧 ) 𝑓 )  ∈  ( 𝑥 𝑗 𝑧 ) ) ) }  ∈  V ) | 
						
							| 13 |  | df-subc | ⊢ Subcat  =  ( 𝑐  ∈  Cat  ↦  { 𝑗  ∣  ( 𝑗  ⊆cat  ( Homf  ‘ 𝑐 )  ∧  [ dom  dom  𝑗  /  𝑠 ] ∀ 𝑥  ∈  𝑠 ( ( ( Id ‘ 𝑐 ) ‘ 𝑥 )  ∈  ( 𝑥 𝑗 𝑥 )  ∧  ∀ 𝑦  ∈  𝑠 ∀ 𝑧  ∈  𝑠 ∀ 𝑓  ∈  ( 𝑥 𝑗 𝑦 ) ∀ 𝑔  ∈  ( 𝑦 𝑗 𝑧 ) ( 𝑔 ( 〈 𝑥 ,  𝑦 〉 ( comp ‘ 𝑐 ) 𝑧 ) 𝑓 )  ∈  ( 𝑥 𝑗 𝑧 ) ) ) } ) | 
						
							| 14 | 13 | fvmpts | ⊢ ( ( 𝐶  ∈  Cat  ∧  ⦋ 𝐶  /  𝑐 ⦌ { 𝑗  ∣  ( 𝑗  ⊆cat  ( Homf  ‘ 𝑐 )  ∧  [ dom  dom  𝑗  /  𝑠 ] ∀ 𝑥  ∈  𝑠 ( ( ( Id ‘ 𝑐 ) ‘ 𝑥 )  ∈  ( 𝑥 𝑗 𝑥 )  ∧  ∀ 𝑦  ∈  𝑠 ∀ 𝑧  ∈  𝑠 ∀ 𝑓  ∈  ( 𝑥 𝑗 𝑦 ) ∀ 𝑔  ∈  ( 𝑦 𝑗 𝑧 ) ( 𝑔 ( 〈 𝑥 ,  𝑦 〉 ( comp ‘ 𝑐 ) 𝑧 ) 𝑓 )  ∈  ( 𝑥 𝑗 𝑧 ) ) ) }  ∈  V )  →  ( Subcat ‘ 𝐶 )  =  ⦋ 𝐶  /  𝑐 ⦌ { 𝑗  ∣  ( 𝑗  ⊆cat  ( Homf  ‘ 𝑐 )  ∧  [ dom  dom  𝑗  /  𝑠 ] ∀ 𝑥  ∈  𝑠 ( ( ( Id ‘ 𝑐 ) ‘ 𝑥 )  ∈  ( 𝑥 𝑗 𝑥 )  ∧  ∀ 𝑦  ∈  𝑠 ∀ 𝑧  ∈  𝑠 ∀ 𝑓  ∈  ( 𝑥 𝑗 𝑦 ) ∀ 𝑔  ∈  ( 𝑦 𝑗 𝑧 ) ( 𝑔 ( 〈 𝑥 ,  𝑦 〉 ( comp ‘ 𝑐 ) 𝑧 ) 𝑓 )  ∈  ( 𝑥 𝑗 𝑧 ) ) ) } ) | 
						
							| 15 | 6 12 14 | syl2anc | ⊢ ( ( 𝐶  ∈  Cat  ∧  𝑆  =  dom  dom  𝐽 )  →  ( Subcat ‘ 𝐶 )  =  ⦋ 𝐶  /  𝑐 ⦌ { 𝑗  ∣  ( 𝑗  ⊆cat  ( Homf  ‘ 𝑐 )  ∧  [ dom  dom  𝑗  /  𝑠 ] ∀ 𝑥  ∈  𝑠 ( ( ( Id ‘ 𝑐 ) ‘ 𝑥 )  ∈  ( 𝑥 𝑗 𝑥 )  ∧  ∀ 𝑦  ∈  𝑠 ∀ 𝑧  ∈  𝑠 ∀ 𝑓  ∈  ( 𝑥 𝑗 𝑦 ) ∀ 𝑔  ∈  ( 𝑦 𝑗 𝑧 ) ( 𝑔 ( 〈 𝑥 ,  𝑦 〉 ( comp ‘ 𝑐 ) 𝑧 ) 𝑓 )  ∈  ( 𝑥 𝑗 𝑧 ) ) ) } ) | 
						
							| 16 | 15 | eleq2d | ⊢ ( ( 𝐶  ∈  Cat  ∧  𝑆  =  dom  dom  𝐽 )  →  ( 𝐽  ∈  ( Subcat ‘ 𝐶 )  ↔  𝐽  ∈  ⦋ 𝐶  /  𝑐 ⦌ { 𝑗  ∣  ( 𝑗  ⊆cat  ( Homf  ‘ 𝑐 )  ∧  [ dom  dom  𝑗  /  𝑠 ] ∀ 𝑥  ∈  𝑠 ( ( ( Id ‘ 𝑐 ) ‘ 𝑥 )  ∈  ( 𝑥 𝑗 𝑥 )  ∧  ∀ 𝑦  ∈  𝑠 ∀ 𝑧  ∈  𝑠 ∀ 𝑓  ∈  ( 𝑥 𝑗 𝑦 ) ∀ 𝑔  ∈  ( 𝑦 𝑗 𝑧 ) ( 𝑔 ( 〈 𝑥 ,  𝑦 〉 ( comp ‘ 𝑐 ) 𝑧 ) 𝑓 )  ∈  ( 𝑥 𝑗 𝑧 ) ) ) } ) ) | 
						
							| 17 |  | sbcel2 | ⊢ ( [ 𝐶  /  𝑐 ] 𝐽  ∈  { 𝑗  ∣  ( 𝑗  ⊆cat  ( Homf  ‘ 𝑐 )  ∧  [ dom  dom  𝑗  /  𝑠 ] ∀ 𝑥  ∈  𝑠 ( ( ( Id ‘ 𝑐 ) ‘ 𝑥 )  ∈  ( 𝑥 𝑗 𝑥 )  ∧  ∀ 𝑦  ∈  𝑠 ∀ 𝑧  ∈  𝑠 ∀ 𝑓  ∈  ( 𝑥 𝑗 𝑦 ) ∀ 𝑔  ∈  ( 𝑦 𝑗 𝑧 ) ( 𝑔 ( 〈 𝑥 ,  𝑦 〉 ( comp ‘ 𝑐 ) 𝑧 ) 𝑓 )  ∈  ( 𝑥 𝑗 𝑧 ) ) ) }  ↔  𝐽  ∈  ⦋ 𝐶  /  𝑐 ⦌ { 𝑗  ∣  ( 𝑗  ⊆cat  ( Homf  ‘ 𝑐 )  ∧  [ dom  dom  𝑗  /  𝑠 ] ∀ 𝑥  ∈  𝑠 ( ( ( Id ‘ 𝑐 ) ‘ 𝑥 )  ∈  ( 𝑥 𝑗 𝑥 )  ∧  ∀ 𝑦  ∈  𝑠 ∀ 𝑧  ∈  𝑠 ∀ 𝑓  ∈  ( 𝑥 𝑗 𝑦 ) ∀ 𝑔  ∈  ( 𝑦 𝑗 𝑧 ) ( 𝑔 ( 〈 𝑥 ,  𝑦 〉 ( comp ‘ 𝑐 ) 𝑧 ) 𝑓 )  ∈  ( 𝑥 𝑗 𝑧 ) ) ) } ) | 
						
							| 18 | 17 | a1i | ⊢ ( ( 𝐶  ∈  Cat  ∧  𝑆  =  dom  dom  𝐽 )  →  ( [ 𝐶  /  𝑐 ] 𝐽  ∈  { 𝑗  ∣  ( 𝑗  ⊆cat  ( Homf  ‘ 𝑐 )  ∧  [ dom  dom  𝑗  /  𝑠 ] ∀ 𝑥  ∈  𝑠 ( ( ( Id ‘ 𝑐 ) ‘ 𝑥 )  ∈  ( 𝑥 𝑗 𝑥 )  ∧  ∀ 𝑦  ∈  𝑠 ∀ 𝑧  ∈  𝑠 ∀ 𝑓  ∈  ( 𝑥 𝑗 𝑦 ) ∀ 𝑔  ∈  ( 𝑦 𝑗 𝑧 ) ( 𝑔 ( 〈 𝑥 ,  𝑦 〉 ( comp ‘ 𝑐 ) 𝑧 ) 𝑓 )  ∈  ( 𝑥 𝑗 𝑧 ) ) ) }  ↔  𝐽  ∈  ⦋ 𝐶  /  𝑐 ⦌ { 𝑗  ∣  ( 𝑗  ⊆cat  ( Homf  ‘ 𝑐 )  ∧  [ dom  dom  𝑗  /  𝑠 ] ∀ 𝑥  ∈  𝑠 ( ( ( Id ‘ 𝑐 ) ‘ 𝑥 )  ∈  ( 𝑥 𝑗 𝑥 )  ∧  ∀ 𝑦  ∈  𝑠 ∀ 𝑧  ∈  𝑠 ∀ 𝑓  ∈  ( 𝑥 𝑗 𝑦 ) ∀ 𝑔  ∈  ( 𝑦 𝑗 𝑧 ) ( 𝑔 ( 〈 𝑥 ,  𝑦 〉 ( comp ‘ 𝑐 ) 𝑧 ) 𝑓 )  ∈  ( 𝑥 𝑗 𝑧 ) ) ) } ) ) | 
						
							| 19 |  | elex | ⊢ ( 𝐽  ∈  { 𝑗  ∣  ( 𝑗  ⊆cat  ( Homf  ‘ 𝑐 )  ∧  [ dom  dom  𝑗  /  𝑠 ] ∀ 𝑥  ∈  𝑠 ( ( ( Id ‘ 𝑐 ) ‘ 𝑥 )  ∈  ( 𝑥 𝑗 𝑥 )  ∧  ∀ 𝑦  ∈  𝑠 ∀ 𝑧  ∈  𝑠 ∀ 𝑓  ∈  ( 𝑥 𝑗 𝑦 ) ∀ 𝑔  ∈  ( 𝑦 𝑗 𝑧 ) ( 𝑔 ( 〈 𝑥 ,  𝑦 〉 ( comp ‘ 𝑐 ) 𝑧 ) 𝑓 )  ∈  ( 𝑥 𝑗 𝑧 ) ) ) }  →  𝐽  ∈  V ) | 
						
							| 20 | 19 | a1i | ⊢ ( ( ( 𝐶  ∈  Cat  ∧  𝑆  =  dom  dom  𝐽 )  ∧  𝑐  =  𝐶 )  →  ( 𝐽  ∈  { 𝑗  ∣  ( 𝑗  ⊆cat  ( Homf  ‘ 𝑐 )  ∧  [ dom  dom  𝑗  /  𝑠 ] ∀ 𝑥  ∈  𝑠 ( ( ( Id ‘ 𝑐 ) ‘ 𝑥 )  ∈  ( 𝑥 𝑗 𝑥 )  ∧  ∀ 𝑦  ∈  𝑠 ∀ 𝑧  ∈  𝑠 ∀ 𝑓  ∈  ( 𝑥 𝑗 𝑦 ) ∀ 𝑔  ∈  ( 𝑦 𝑗 𝑧 ) ( 𝑔 ( 〈 𝑥 ,  𝑦 〉 ( comp ‘ 𝑐 ) 𝑧 ) 𝑓 )  ∈  ( 𝑥 𝑗 𝑧 ) ) ) }  →  𝐽  ∈  V ) ) | 
						
							| 21 |  | sscrel | ⊢ Rel   ⊆cat | 
						
							| 22 | 21 | brrelex1i | ⊢ ( 𝐽  ⊆cat  𝐻  →  𝐽  ∈  V ) | 
						
							| 23 | 22 | adantr | ⊢ ( ( 𝐽  ⊆cat  𝐻  ∧  ∀ 𝑥  ∈  𝑆 ( (  1  ‘ 𝑥 )  ∈  ( 𝑥 𝐽 𝑥 )  ∧  ∀ 𝑦  ∈  𝑆 ∀ 𝑧  ∈  𝑆 ∀ 𝑓  ∈  ( 𝑥 𝐽 𝑦 ) ∀ 𝑔  ∈  ( 𝑦 𝐽 𝑧 ) ( 𝑔 ( 〈 𝑥 ,  𝑦 〉  ·  𝑧 ) 𝑓 )  ∈  ( 𝑥 𝐽 𝑧 ) ) )  →  𝐽  ∈  V ) | 
						
							| 24 | 23 | a1i | ⊢ ( ( ( 𝐶  ∈  Cat  ∧  𝑆  =  dom  dom  𝐽 )  ∧  𝑐  =  𝐶 )  →  ( ( 𝐽  ⊆cat  𝐻  ∧  ∀ 𝑥  ∈  𝑆 ( (  1  ‘ 𝑥 )  ∈  ( 𝑥 𝐽 𝑥 )  ∧  ∀ 𝑦  ∈  𝑆 ∀ 𝑧  ∈  𝑆 ∀ 𝑓  ∈  ( 𝑥 𝐽 𝑦 ) ∀ 𝑔  ∈  ( 𝑦 𝐽 𝑧 ) ( 𝑔 ( 〈 𝑥 ,  𝑦 〉  ·  𝑧 ) 𝑓 )  ∈  ( 𝑥 𝐽 𝑧 ) ) )  →  𝐽  ∈  V ) ) | 
						
							| 25 |  | df-sbc | ⊢ ( [ 𝐽  /  𝑗 ] ( 𝑗  ⊆cat  ( Homf  ‘ 𝑐 )  ∧  [ dom  dom  𝑗  /  𝑠 ] ∀ 𝑥  ∈  𝑠 ( ( ( Id ‘ 𝑐 ) ‘ 𝑥 )  ∈  ( 𝑥 𝑗 𝑥 )  ∧  ∀ 𝑦  ∈  𝑠 ∀ 𝑧  ∈  𝑠 ∀ 𝑓  ∈  ( 𝑥 𝑗 𝑦 ) ∀ 𝑔  ∈  ( 𝑦 𝑗 𝑧 ) ( 𝑔 ( 〈 𝑥 ,  𝑦 〉 ( comp ‘ 𝑐 ) 𝑧 ) 𝑓 )  ∈  ( 𝑥 𝑗 𝑧 ) ) )  ↔  𝐽  ∈  { 𝑗  ∣  ( 𝑗  ⊆cat  ( Homf  ‘ 𝑐 )  ∧  [ dom  dom  𝑗  /  𝑠 ] ∀ 𝑥  ∈  𝑠 ( ( ( Id ‘ 𝑐 ) ‘ 𝑥 )  ∈  ( 𝑥 𝑗 𝑥 )  ∧  ∀ 𝑦  ∈  𝑠 ∀ 𝑧  ∈  𝑠 ∀ 𝑓  ∈  ( 𝑥 𝑗 𝑦 ) ∀ 𝑔  ∈  ( 𝑦 𝑗 𝑧 ) ( 𝑔 ( 〈 𝑥 ,  𝑦 〉 ( comp ‘ 𝑐 ) 𝑧 ) 𝑓 )  ∈  ( 𝑥 𝑗 𝑧 ) ) ) } ) | 
						
							| 26 |  | simpr | ⊢ ( ( ( ( 𝐶  ∈  Cat  ∧  𝑆  =  dom  dom  𝐽 )  ∧  𝑐  =  𝐶 )  ∧  𝐽  ∈  V )  →  𝐽  ∈  V ) | 
						
							| 27 |  | simpr | ⊢ ( ( ( ( 𝐶  ∈  Cat  ∧  𝑆  =  dom  dom  𝐽 )  ∧  𝑐  =  𝐶 )  ∧  𝑗  =  𝐽 )  →  𝑗  =  𝐽 ) | 
						
							| 28 |  | simpr | ⊢ ( ( ( 𝐶  ∈  Cat  ∧  𝑆  =  dom  dom  𝐽 )  ∧  𝑐  =  𝐶 )  →  𝑐  =  𝐶 ) | 
						
							| 29 | 28 | fveq2d | ⊢ ( ( ( 𝐶  ∈  Cat  ∧  𝑆  =  dom  dom  𝐽 )  ∧  𝑐  =  𝐶 )  →  ( Homf  ‘ 𝑐 )  =  ( Homf  ‘ 𝐶 ) ) | 
						
							| 30 | 29 1 | eqtr4di | ⊢ ( ( ( 𝐶  ∈  Cat  ∧  𝑆  =  dom  dom  𝐽 )  ∧  𝑐  =  𝐶 )  →  ( Homf  ‘ 𝑐 )  =  𝐻 ) | 
						
							| 31 | 30 | adantr | ⊢ ( ( ( ( 𝐶  ∈  Cat  ∧  𝑆  =  dom  dom  𝐽 )  ∧  𝑐  =  𝐶 )  ∧  𝑗  =  𝐽 )  →  ( Homf  ‘ 𝑐 )  =  𝐻 ) | 
						
							| 32 | 27 31 | breq12d | ⊢ ( ( ( ( 𝐶  ∈  Cat  ∧  𝑆  =  dom  dom  𝐽 )  ∧  𝑐  =  𝐶 )  ∧  𝑗  =  𝐽 )  →  ( 𝑗  ⊆cat  ( Homf  ‘ 𝑐 )  ↔  𝐽  ⊆cat  𝐻 ) ) | 
						
							| 33 |  | vex | ⊢ 𝑗  ∈  V | 
						
							| 34 | 33 | dmex | ⊢ dom  𝑗  ∈  V | 
						
							| 35 | 34 | dmex | ⊢ dom  dom  𝑗  ∈  V | 
						
							| 36 | 35 | a1i | ⊢ ( ( ( ( 𝐶  ∈  Cat  ∧  𝑆  =  dom  dom  𝐽 )  ∧  𝑐  =  𝐶 )  ∧  𝑗  =  𝐽 )  →  dom  dom  𝑗  ∈  V ) | 
						
							| 37 | 27 | dmeqd | ⊢ ( ( ( ( 𝐶  ∈  Cat  ∧  𝑆  =  dom  dom  𝐽 )  ∧  𝑐  =  𝐶 )  ∧  𝑗  =  𝐽 )  →  dom  𝑗  =  dom  𝐽 ) | 
						
							| 38 | 37 | dmeqd | ⊢ ( ( ( ( 𝐶  ∈  Cat  ∧  𝑆  =  dom  dom  𝐽 )  ∧  𝑐  =  𝐶 )  ∧  𝑗  =  𝐽 )  →  dom  dom  𝑗  =  dom  dom  𝐽 ) | 
						
							| 39 |  | simpllr | ⊢ ( ( ( ( 𝐶  ∈  Cat  ∧  𝑆  =  dom  dom  𝐽 )  ∧  𝑐  =  𝐶 )  ∧  𝑗  =  𝐽 )  →  𝑆  =  dom  dom  𝐽 ) | 
						
							| 40 | 38 39 | eqtr4d | ⊢ ( ( ( ( 𝐶  ∈  Cat  ∧  𝑆  =  dom  dom  𝐽 )  ∧  𝑐  =  𝐶 )  ∧  𝑗  =  𝐽 )  →  dom  dom  𝑗  =  𝑆 ) | 
						
							| 41 |  | simpr | ⊢ ( ( ( ( ( 𝐶  ∈  Cat  ∧  𝑆  =  dom  dom  𝐽 )  ∧  𝑐  =  𝐶 )  ∧  𝑗  =  𝐽 )  ∧  𝑠  =  𝑆 )  →  𝑠  =  𝑆 ) | 
						
							| 42 |  | simpllr | ⊢ ( ( ( ( ( 𝐶  ∈  Cat  ∧  𝑆  =  dom  dom  𝐽 )  ∧  𝑐  =  𝐶 )  ∧  𝑗  =  𝐽 )  ∧  𝑠  =  𝑆 )  →  𝑐  =  𝐶 ) | 
						
							| 43 | 42 | fveq2d | ⊢ ( ( ( ( ( 𝐶  ∈  Cat  ∧  𝑆  =  dom  dom  𝐽 )  ∧  𝑐  =  𝐶 )  ∧  𝑗  =  𝐽 )  ∧  𝑠  =  𝑆 )  →  ( Id ‘ 𝑐 )  =  ( Id ‘ 𝐶 ) ) | 
						
							| 44 | 43 2 | eqtr4di | ⊢ ( ( ( ( ( 𝐶  ∈  Cat  ∧  𝑆  =  dom  dom  𝐽 )  ∧  𝑐  =  𝐶 )  ∧  𝑗  =  𝐽 )  ∧  𝑠  =  𝑆 )  →  ( Id ‘ 𝑐 )  =   1  ) | 
						
							| 45 | 44 | fveq1d | ⊢ ( ( ( ( ( 𝐶  ∈  Cat  ∧  𝑆  =  dom  dom  𝐽 )  ∧  𝑐  =  𝐶 )  ∧  𝑗  =  𝐽 )  ∧  𝑠  =  𝑆 )  →  ( ( Id ‘ 𝑐 ) ‘ 𝑥 )  =  (  1  ‘ 𝑥 ) ) | 
						
							| 46 |  | simplr | ⊢ ( ( ( ( ( 𝐶  ∈  Cat  ∧  𝑆  =  dom  dom  𝐽 )  ∧  𝑐  =  𝐶 )  ∧  𝑗  =  𝐽 )  ∧  𝑠  =  𝑆 )  →  𝑗  =  𝐽 ) | 
						
							| 47 | 46 | oveqd | ⊢ ( ( ( ( ( 𝐶  ∈  Cat  ∧  𝑆  =  dom  dom  𝐽 )  ∧  𝑐  =  𝐶 )  ∧  𝑗  =  𝐽 )  ∧  𝑠  =  𝑆 )  →  ( 𝑥 𝑗 𝑥 )  =  ( 𝑥 𝐽 𝑥 ) ) | 
						
							| 48 | 45 47 | eleq12d | ⊢ ( ( ( ( ( 𝐶  ∈  Cat  ∧  𝑆  =  dom  dom  𝐽 )  ∧  𝑐  =  𝐶 )  ∧  𝑗  =  𝐽 )  ∧  𝑠  =  𝑆 )  →  ( ( ( Id ‘ 𝑐 ) ‘ 𝑥 )  ∈  ( 𝑥 𝑗 𝑥 )  ↔  (  1  ‘ 𝑥 )  ∈  ( 𝑥 𝐽 𝑥 ) ) ) | 
						
							| 49 | 46 | oveqd | ⊢ ( ( ( ( ( 𝐶  ∈  Cat  ∧  𝑆  =  dom  dom  𝐽 )  ∧  𝑐  =  𝐶 )  ∧  𝑗  =  𝐽 )  ∧  𝑠  =  𝑆 )  →  ( 𝑥 𝑗 𝑦 )  =  ( 𝑥 𝐽 𝑦 ) ) | 
						
							| 50 | 46 | oveqd | ⊢ ( ( ( ( ( 𝐶  ∈  Cat  ∧  𝑆  =  dom  dom  𝐽 )  ∧  𝑐  =  𝐶 )  ∧  𝑗  =  𝐽 )  ∧  𝑠  =  𝑆 )  →  ( 𝑦 𝑗 𝑧 )  =  ( 𝑦 𝐽 𝑧 ) ) | 
						
							| 51 | 42 | fveq2d | ⊢ ( ( ( ( ( 𝐶  ∈  Cat  ∧  𝑆  =  dom  dom  𝐽 )  ∧  𝑐  =  𝐶 )  ∧  𝑗  =  𝐽 )  ∧  𝑠  =  𝑆 )  →  ( comp ‘ 𝑐 )  =  ( comp ‘ 𝐶 ) ) | 
						
							| 52 | 51 3 | eqtr4di | ⊢ ( ( ( ( ( 𝐶  ∈  Cat  ∧  𝑆  =  dom  dom  𝐽 )  ∧  𝑐  =  𝐶 )  ∧  𝑗  =  𝐽 )  ∧  𝑠  =  𝑆 )  →  ( comp ‘ 𝑐 )  =   ·  ) | 
						
							| 53 | 52 | oveqd | ⊢ ( ( ( ( ( 𝐶  ∈  Cat  ∧  𝑆  =  dom  dom  𝐽 )  ∧  𝑐  =  𝐶 )  ∧  𝑗  =  𝐽 )  ∧  𝑠  =  𝑆 )  →  ( 〈 𝑥 ,  𝑦 〉 ( comp ‘ 𝑐 ) 𝑧 )  =  ( 〈 𝑥 ,  𝑦 〉  ·  𝑧 ) ) | 
						
							| 54 | 53 | oveqd | ⊢ ( ( ( ( ( 𝐶  ∈  Cat  ∧  𝑆  =  dom  dom  𝐽 )  ∧  𝑐  =  𝐶 )  ∧  𝑗  =  𝐽 )  ∧  𝑠  =  𝑆 )  →  ( 𝑔 ( 〈 𝑥 ,  𝑦 〉 ( comp ‘ 𝑐 ) 𝑧 ) 𝑓 )  =  ( 𝑔 ( 〈 𝑥 ,  𝑦 〉  ·  𝑧 ) 𝑓 ) ) | 
						
							| 55 | 46 | oveqd | ⊢ ( ( ( ( ( 𝐶  ∈  Cat  ∧  𝑆  =  dom  dom  𝐽 )  ∧  𝑐  =  𝐶 )  ∧  𝑗  =  𝐽 )  ∧  𝑠  =  𝑆 )  →  ( 𝑥 𝑗 𝑧 )  =  ( 𝑥 𝐽 𝑧 ) ) | 
						
							| 56 | 54 55 | eleq12d | ⊢ ( ( ( ( ( 𝐶  ∈  Cat  ∧  𝑆  =  dom  dom  𝐽 )  ∧  𝑐  =  𝐶 )  ∧  𝑗  =  𝐽 )  ∧  𝑠  =  𝑆 )  →  ( ( 𝑔 ( 〈 𝑥 ,  𝑦 〉 ( comp ‘ 𝑐 ) 𝑧 ) 𝑓 )  ∈  ( 𝑥 𝑗 𝑧 )  ↔  ( 𝑔 ( 〈 𝑥 ,  𝑦 〉  ·  𝑧 ) 𝑓 )  ∈  ( 𝑥 𝐽 𝑧 ) ) ) | 
						
							| 57 | 50 56 | raleqbidv | ⊢ ( ( ( ( ( 𝐶  ∈  Cat  ∧  𝑆  =  dom  dom  𝐽 )  ∧  𝑐  =  𝐶 )  ∧  𝑗  =  𝐽 )  ∧  𝑠  =  𝑆 )  →  ( ∀ 𝑔  ∈  ( 𝑦 𝑗 𝑧 ) ( 𝑔 ( 〈 𝑥 ,  𝑦 〉 ( comp ‘ 𝑐 ) 𝑧 ) 𝑓 )  ∈  ( 𝑥 𝑗 𝑧 )  ↔  ∀ 𝑔  ∈  ( 𝑦 𝐽 𝑧 ) ( 𝑔 ( 〈 𝑥 ,  𝑦 〉  ·  𝑧 ) 𝑓 )  ∈  ( 𝑥 𝐽 𝑧 ) ) ) | 
						
							| 58 | 49 57 | raleqbidv | ⊢ ( ( ( ( ( 𝐶  ∈  Cat  ∧  𝑆  =  dom  dom  𝐽 )  ∧  𝑐  =  𝐶 )  ∧  𝑗  =  𝐽 )  ∧  𝑠  =  𝑆 )  →  ( ∀ 𝑓  ∈  ( 𝑥 𝑗 𝑦 ) ∀ 𝑔  ∈  ( 𝑦 𝑗 𝑧 ) ( 𝑔 ( 〈 𝑥 ,  𝑦 〉 ( comp ‘ 𝑐 ) 𝑧 ) 𝑓 )  ∈  ( 𝑥 𝑗 𝑧 )  ↔  ∀ 𝑓  ∈  ( 𝑥 𝐽 𝑦 ) ∀ 𝑔  ∈  ( 𝑦 𝐽 𝑧 ) ( 𝑔 ( 〈 𝑥 ,  𝑦 〉  ·  𝑧 ) 𝑓 )  ∈  ( 𝑥 𝐽 𝑧 ) ) ) | 
						
							| 59 | 41 58 | raleqbidv | ⊢ ( ( ( ( ( 𝐶  ∈  Cat  ∧  𝑆  =  dom  dom  𝐽 )  ∧  𝑐  =  𝐶 )  ∧  𝑗  =  𝐽 )  ∧  𝑠  =  𝑆 )  →  ( ∀ 𝑧  ∈  𝑠 ∀ 𝑓  ∈  ( 𝑥 𝑗 𝑦 ) ∀ 𝑔  ∈  ( 𝑦 𝑗 𝑧 ) ( 𝑔 ( 〈 𝑥 ,  𝑦 〉 ( comp ‘ 𝑐 ) 𝑧 ) 𝑓 )  ∈  ( 𝑥 𝑗 𝑧 )  ↔  ∀ 𝑧  ∈  𝑆 ∀ 𝑓  ∈  ( 𝑥 𝐽 𝑦 ) ∀ 𝑔  ∈  ( 𝑦 𝐽 𝑧 ) ( 𝑔 ( 〈 𝑥 ,  𝑦 〉  ·  𝑧 ) 𝑓 )  ∈  ( 𝑥 𝐽 𝑧 ) ) ) | 
						
							| 60 | 41 59 | raleqbidv | ⊢ ( ( ( ( ( 𝐶  ∈  Cat  ∧  𝑆  =  dom  dom  𝐽 )  ∧  𝑐  =  𝐶 )  ∧  𝑗  =  𝐽 )  ∧  𝑠  =  𝑆 )  →  ( ∀ 𝑦  ∈  𝑠 ∀ 𝑧  ∈  𝑠 ∀ 𝑓  ∈  ( 𝑥 𝑗 𝑦 ) ∀ 𝑔  ∈  ( 𝑦 𝑗 𝑧 ) ( 𝑔 ( 〈 𝑥 ,  𝑦 〉 ( comp ‘ 𝑐 ) 𝑧 ) 𝑓 )  ∈  ( 𝑥 𝑗 𝑧 )  ↔  ∀ 𝑦  ∈  𝑆 ∀ 𝑧  ∈  𝑆 ∀ 𝑓  ∈  ( 𝑥 𝐽 𝑦 ) ∀ 𝑔  ∈  ( 𝑦 𝐽 𝑧 ) ( 𝑔 ( 〈 𝑥 ,  𝑦 〉  ·  𝑧 ) 𝑓 )  ∈  ( 𝑥 𝐽 𝑧 ) ) ) | 
						
							| 61 | 48 60 | anbi12d | ⊢ ( ( ( ( ( 𝐶  ∈  Cat  ∧  𝑆  =  dom  dom  𝐽 )  ∧  𝑐  =  𝐶 )  ∧  𝑗  =  𝐽 )  ∧  𝑠  =  𝑆 )  →  ( ( ( ( Id ‘ 𝑐 ) ‘ 𝑥 )  ∈  ( 𝑥 𝑗 𝑥 )  ∧  ∀ 𝑦  ∈  𝑠 ∀ 𝑧  ∈  𝑠 ∀ 𝑓  ∈  ( 𝑥 𝑗 𝑦 ) ∀ 𝑔  ∈  ( 𝑦 𝑗 𝑧 ) ( 𝑔 ( 〈 𝑥 ,  𝑦 〉 ( comp ‘ 𝑐 ) 𝑧 ) 𝑓 )  ∈  ( 𝑥 𝑗 𝑧 ) )  ↔  ( (  1  ‘ 𝑥 )  ∈  ( 𝑥 𝐽 𝑥 )  ∧  ∀ 𝑦  ∈  𝑆 ∀ 𝑧  ∈  𝑆 ∀ 𝑓  ∈  ( 𝑥 𝐽 𝑦 ) ∀ 𝑔  ∈  ( 𝑦 𝐽 𝑧 ) ( 𝑔 ( 〈 𝑥 ,  𝑦 〉  ·  𝑧 ) 𝑓 )  ∈  ( 𝑥 𝐽 𝑧 ) ) ) ) | 
						
							| 62 | 41 61 | raleqbidv | ⊢ ( ( ( ( ( 𝐶  ∈  Cat  ∧  𝑆  =  dom  dom  𝐽 )  ∧  𝑐  =  𝐶 )  ∧  𝑗  =  𝐽 )  ∧  𝑠  =  𝑆 )  →  ( ∀ 𝑥  ∈  𝑠 ( ( ( Id ‘ 𝑐 ) ‘ 𝑥 )  ∈  ( 𝑥 𝑗 𝑥 )  ∧  ∀ 𝑦  ∈  𝑠 ∀ 𝑧  ∈  𝑠 ∀ 𝑓  ∈  ( 𝑥 𝑗 𝑦 ) ∀ 𝑔  ∈  ( 𝑦 𝑗 𝑧 ) ( 𝑔 ( 〈 𝑥 ,  𝑦 〉 ( comp ‘ 𝑐 ) 𝑧 ) 𝑓 )  ∈  ( 𝑥 𝑗 𝑧 ) )  ↔  ∀ 𝑥  ∈  𝑆 ( (  1  ‘ 𝑥 )  ∈  ( 𝑥 𝐽 𝑥 )  ∧  ∀ 𝑦  ∈  𝑆 ∀ 𝑧  ∈  𝑆 ∀ 𝑓  ∈  ( 𝑥 𝐽 𝑦 ) ∀ 𝑔  ∈  ( 𝑦 𝐽 𝑧 ) ( 𝑔 ( 〈 𝑥 ,  𝑦 〉  ·  𝑧 ) 𝑓 )  ∈  ( 𝑥 𝐽 𝑧 ) ) ) ) | 
						
							| 63 | 36 40 62 | sbcied2 | ⊢ ( ( ( ( 𝐶  ∈  Cat  ∧  𝑆  =  dom  dom  𝐽 )  ∧  𝑐  =  𝐶 )  ∧  𝑗  =  𝐽 )  →  ( [ dom  dom  𝑗  /  𝑠 ] ∀ 𝑥  ∈  𝑠 ( ( ( Id ‘ 𝑐 ) ‘ 𝑥 )  ∈  ( 𝑥 𝑗 𝑥 )  ∧  ∀ 𝑦  ∈  𝑠 ∀ 𝑧  ∈  𝑠 ∀ 𝑓  ∈  ( 𝑥 𝑗 𝑦 ) ∀ 𝑔  ∈  ( 𝑦 𝑗 𝑧 ) ( 𝑔 ( 〈 𝑥 ,  𝑦 〉 ( comp ‘ 𝑐 ) 𝑧 ) 𝑓 )  ∈  ( 𝑥 𝑗 𝑧 ) )  ↔  ∀ 𝑥  ∈  𝑆 ( (  1  ‘ 𝑥 )  ∈  ( 𝑥 𝐽 𝑥 )  ∧  ∀ 𝑦  ∈  𝑆 ∀ 𝑧  ∈  𝑆 ∀ 𝑓  ∈  ( 𝑥 𝐽 𝑦 ) ∀ 𝑔  ∈  ( 𝑦 𝐽 𝑧 ) ( 𝑔 ( 〈 𝑥 ,  𝑦 〉  ·  𝑧 ) 𝑓 )  ∈  ( 𝑥 𝐽 𝑧 ) ) ) ) | 
						
							| 64 | 32 63 | anbi12d | ⊢ ( ( ( ( 𝐶  ∈  Cat  ∧  𝑆  =  dom  dom  𝐽 )  ∧  𝑐  =  𝐶 )  ∧  𝑗  =  𝐽 )  →  ( ( 𝑗  ⊆cat  ( Homf  ‘ 𝑐 )  ∧  [ dom  dom  𝑗  /  𝑠 ] ∀ 𝑥  ∈  𝑠 ( ( ( Id ‘ 𝑐 ) ‘ 𝑥 )  ∈  ( 𝑥 𝑗 𝑥 )  ∧  ∀ 𝑦  ∈  𝑠 ∀ 𝑧  ∈  𝑠 ∀ 𝑓  ∈  ( 𝑥 𝑗 𝑦 ) ∀ 𝑔  ∈  ( 𝑦 𝑗 𝑧 ) ( 𝑔 ( 〈 𝑥 ,  𝑦 〉 ( comp ‘ 𝑐 ) 𝑧 ) 𝑓 )  ∈  ( 𝑥 𝑗 𝑧 ) ) )  ↔  ( 𝐽  ⊆cat  𝐻  ∧  ∀ 𝑥  ∈  𝑆 ( (  1  ‘ 𝑥 )  ∈  ( 𝑥 𝐽 𝑥 )  ∧  ∀ 𝑦  ∈  𝑆 ∀ 𝑧  ∈  𝑆 ∀ 𝑓  ∈  ( 𝑥 𝐽 𝑦 ) ∀ 𝑔  ∈  ( 𝑦 𝐽 𝑧 ) ( 𝑔 ( 〈 𝑥 ,  𝑦 〉  ·  𝑧 ) 𝑓 )  ∈  ( 𝑥 𝐽 𝑧 ) ) ) ) ) | 
						
							| 65 | 64 | adantlr | ⊢ ( ( ( ( ( 𝐶  ∈  Cat  ∧  𝑆  =  dom  dom  𝐽 )  ∧  𝑐  =  𝐶 )  ∧  𝐽  ∈  V )  ∧  𝑗  =  𝐽 )  →  ( ( 𝑗  ⊆cat  ( Homf  ‘ 𝑐 )  ∧  [ dom  dom  𝑗  /  𝑠 ] ∀ 𝑥  ∈  𝑠 ( ( ( Id ‘ 𝑐 ) ‘ 𝑥 )  ∈  ( 𝑥 𝑗 𝑥 )  ∧  ∀ 𝑦  ∈  𝑠 ∀ 𝑧  ∈  𝑠 ∀ 𝑓  ∈  ( 𝑥 𝑗 𝑦 ) ∀ 𝑔  ∈  ( 𝑦 𝑗 𝑧 ) ( 𝑔 ( 〈 𝑥 ,  𝑦 〉 ( comp ‘ 𝑐 ) 𝑧 ) 𝑓 )  ∈  ( 𝑥 𝑗 𝑧 ) ) )  ↔  ( 𝐽  ⊆cat  𝐻  ∧  ∀ 𝑥  ∈  𝑆 ( (  1  ‘ 𝑥 )  ∈  ( 𝑥 𝐽 𝑥 )  ∧  ∀ 𝑦  ∈  𝑆 ∀ 𝑧  ∈  𝑆 ∀ 𝑓  ∈  ( 𝑥 𝐽 𝑦 ) ∀ 𝑔  ∈  ( 𝑦 𝐽 𝑧 ) ( 𝑔 ( 〈 𝑥 ,  𝑦 〉  ·  𝑧 ) 𝑓 )  ∈  ( 𝑥 𝐽 𝑧 ) ) ) ) ) | 
						
							| 66 | 26 65 | sbcied | ⊢ ( ( ( ( 𝐶  ∈  Cat  ∧  𝑆  =  dom  dom  𝐽 )  ∧  𝑐  =  𝐶 )  ∧  𝐽  ∈  V )  →  ( [ 𝐽  /  𝑗 ] ( 𝑗  ⊆cat  ( Homf  ‘ 𝑐 )  ∧  [ dom  dom  𝑗  /  𝑠 ] ∀ 𝑥  ∈  𝑠 ( ( ( Id ‘ 𝑐 ) ‘ 𝑥 )  ∈  ( 𝑥 𝑗 𝑥 )  ∧  ∀ 𝑦  ∈  𝑠 ∀ 𝑧  ∈  𝑠 ∀ 𝑓  ∈  ( 𝑥 𝑗 𝑦 ) ∀ 𝑔  ∈  ( 𝑦 𝑗 𝑧 ) ( 𝑔 ( 〈 𝑥 ,  𝑦 〉 ( comp ‘ 𝑐 ) 𝑧 ) 𝑓 )  ∈  ( 𝑥 𝑗 𝑧 ) ) )  ↔  ( 𝐽  ⊆cat  𝐻  ∧  ∀ 𝑥  ∈  𝑆 ( (  1  ‘ 𝑥 )  ∈  ( 𝑥 𝐽 𝑥 )  ∧  ∀ 𝑦  ∈  𝑆 ∀ 𝑧  ∈  𝑆 ∀ 𝑓  ∈  ( 𝑥 𝐽 𝑦 ) ∀ 𝑔  ∈  ( 𝑦 𝐽 𝑧 ) ( 𝑔 ( 〈 𝑥 ,  𝑦 〉  ·  𝑧 ) 𝑓 )  ∈  ( 𝑥 𝐽 𝑧 ) ) ) ) ) | 
						
							| 67 | 25 66 | bitr3id | ⊢ ( ( ( ( 𝐶  ∈  Cat  ∧  𝑆  =  dom  dom  𝐽 )  ∧  𝑐  =  𝐶 )  ∧  𝐽  ∈  V )  →  ( 𝐽  ∈  { 𝑗  ∣  ( 𝑗  ⊆cat  ( Homf  ‘ 𝑐 )  ∧  [ dom  dom  𝑗  /  𝑠 ] ∀ 𝑥  ∈  𝑠 ( ( ( Id ‘ 𝑐 ) ‘ 𝑥 )  ∈  ( 𝑥 𝑗 𝑥 )  ∧  ∀ 𝑦  ∈  𝑠 ∀ 𝑧  ∈  𝑠 ∀ 𝑓  ∈  ( 𝑥 𝑗 𝑦 ) ∀ 𝑔  ∈  ( 𝑦 𝑗 𝑧 ) ( 𝑔 ( 〈 𝑥 ,  𝑦 〉 ( comp ‘ 𝑐 ) 𝑧 ) 𝑓 )  ∈  ( 𝑥 𝑗 𝑧 ) ) ) }  ↔  ( 𝐽  ⊆cat  𝐻  ∧  ∀ 𝑥  ∈  𝑆 ( (  1  ‘ 𝑥 )  ∈  ( 𝑥 𝐽 𝑥 )  ∧  ∀ 𝑦  ∈  𝑆 ∀ 𝑧  ∈  𝑆 ∀ 𝑓  ∈  ( 𝑥 𝐽 𝑦 ) ∀ 𝑔  ∈  ( 𝑦 𝐽 𝑧 ) ( 𝑔 ( 〈 𝑥 ,  𝑦 〉  ·  𝑧 ) 𝑓 )  ∈  ( 𝑥 𝐽 𝑧 ) ) ) ) ) | 
						
							| 68 | 67 | ex | ⊢ ( ( ( 𝐶  ∈  Cat  ∧  𝑆  =  dom  dom  𝐽 )  ∧  𝑐  =  𝐶 )  →  ( 𝐽  ∈  V  →  ( 𝐽  ∈  { 𝑗  ∣  ( 𝑗  ⊆cat  ( Homf  ‘ 𝑐 )  ∧  [ dom  dom  𝑗  /  𝑠 ] ∀ 𝑥  ∈  𝑠 ( ( ( Id ‘ 𝑐 ) ‘ 𝑥 )  ∈  ( 𝑥 𝑗 𝑥 )  ∧  ∀ 𝑦  ∈  𝑠 ∀ 𝑧  ∈  𝑠 ∀ 𝑓  ∈  ( 𝑥 𝑗 𝑦 ) ∀ 𝑔  ∈  ( 𝑦 𝑗 𝑧 ) ( 𝑔 ( 〈 𝑥 ,  𝑦 〉 ( comp ‘ 𝑐 ) 𝑧 ) 𝑓 )  ∈  ( 𝑥 𝑗 𝑧 ) ) ) }  ↔  ( 𝐽  ⊆cat  𝐻  ∧  ∀ 𝑥  ∈  𝑆 ( (  1  ‘ 𝑥 )  ∈  ( 𝑥 𝐽 𝑥 )  ∧  ∀ 𝑦  ∈  𝑆 ∀ 𝑧  ∈  𝑆 ∀ 𝑓  ∈  ( 𝑥 𝐽 𝑦 ) ∀ 𝑔  ∈  ( 𝑦 𝐽 𝑧 ) ( 𝑔 ( 〈 𝑥 ,  𝑦 〉  ·  𝑧 ) 𝑓 )  ∈  ( 𝑥 𝐽 𝑧 ) ) ) ) ) ) | 
						
							| 69 | 20 24 68 | pm5.21ndd | ⊢ ( ( ( 𝐶  ∈  Cat  ∧  𝑆  =  dom  dom  𝐽 )  ∧  𝑐  =  𝐶 )  →  ( 𝐽  ∈  { 𝑗  ∣  ( 𝑗  ⊆cat  ( Homf  ‘ 𝑐 )  ∧  [ dom  dom  𝑗  /  𝑠 ] ∀ 𝑥  ∈  𝑠 ( ( ( Id ‘ 𝑐 ) ‘ 𝑥 )  ∈  ( 𝑥 𝑗 𝑥 )  ∧  ∀ 𝑦  ∈  𝑠 ∀ 𝑧  ∈  𝑠 ∀ 𝑓  ∈  ( 𝑥 𝑗 𝑦 ) ∀ 𝑔  ∈  ( 𝑦 𝑗 𝑧 ) ( 𝑔 ( 〈 𝑥 ,  𝑦 〉 ( comp ‘ 𝑐 ) 𝑧 ) 𝑓 )  ∈  ( 𝑥 𝑗 𝑧 ) ) ) }  ↔  ( 𝐽  ⊆cat  𝐻  ∧  ∀ 𝑥  ∈  𝑆 ( (  1  ‘ 𝑥 )  ∈  ( 𝑥 𝐽 𝑥 )  ∧  ∀ 𝑦  ∈  𝑆 ∀ 𝑧  ∈  𝑆 ∀ 𝑓  ∈  ( 𝑥 𝐽 𝑦 ) ∀ 𝑔  ∈  ( 𝑦 𝐽 𝑧 ) ( 𝑔 ( 〈 𝑥 ,  𝑦 〉  ·  𝑧 ) 𝑓 )  ∈  ( 𝑥 𝐽 𝑧 ) ) ) ) ) | 
						
							| 70 | 6 69 | sbcied | ⊢ ( ( 𝐶  ∈  Cat  ∧  𝑆  =  dom  dom  𝐽 )  →  ( [ 𝐶  /  𝑐 ] 𝐽  ∈  { 𝑗  ∣  ( 𝑗  ⊆cat  ( Homf  ‘ 𝑐 )  ∧  [ dom  dom  𝑗  /  𝑠 ] ∀ 𝑥  ∈  𝑠 ( ( ( Id ‘ 𝑐 ) ‘ 𝑥 )  ∈  ( 𝑥 𝑗 𝑥 )  ∧  ∀ 𝑦  ∈  𝑠 ∀ 𝑧  ∈  𝑠 ∀ 𝑓  ∈  ( 𝑥 𝑗 𝑦 ) ∀ 𝑔  ∈  ( 𝑦 𝑗 𝑧 ) ( 𝑔 ( 〈 𝑥 ,  𝑦 〉 ( comp ‘ 𝑐 ) 𝑧 ) 𝑓 )  ∈  ( 𝑥 𝑗 𝑧 ) ) ) }  ↔  ( 𝐽  ⊆cat  𝐻  ∧  ∀ 𝑥  ∈  𝑆 ( (  1  ‘ 𝑥 )  ∈  ( 𝑥 𝐽 𝑥 )  ∧  ∀ 𝑦  ∈  𝑆 ∀ 𝑧  ∈  𝑆 ∀ 𝑓  ∈  ( 𝑥 𝐽 𝑦 ) ∀ 𝑔  ∈  ( 𝑦 𝐽 𝑧 ) ( 𝑔 ( 〈 𝑥 ,  𝑦 〉  ·  𝑧 ) 𝑓 )  ∈  ( 𝑥 𝐽 𝑧 ) ) ) ) ) | 
						
							| 71 | 16 18 70 | 3bitr2d | ⊢ ( ( 𝐶  ∈  Cat  ∧  𝑆  =  dom  dom  𝐽 )  →  ( 𝐽  ∈  ( Subcat ‘ 𝐶 )  ↔  ( 𝐽  ⊆cat  𝐻  ∧  ∀ 𝑥  ∈  𝑆 ( (  1  ‘ 𝑥 )  ∈  ( 𝑥 𝐽 𝑥 )  ∧  ∀ 𝑦  ∈  𝑆 ∀ 𝑧  ∈  𝑆 ∀ 𝑓  ∈  ( 𝑥 𝐽 𝑦 ) ∀ 𝑔  ∈  ( 𝑦 𝐽 𝑧 ) ( 𝑔 ( 〈 𝑥 ,  𝑦 〉  ·  𝑧 ) 𝑓 )  ∈  ( 𝑥 𝐽 𝑧 ) ) ) ) ) | 
						
							| 72 | 4 5 71 | syl2anc | ⊢ ( 𝜑  →  ( 𝐽  ∈  ( Subcat ‘ 𝐶 )  ↔  ( 𝐽  ⊆cat  𝐻  ∧  ∀ 𝑥  ∈  𝑆 ( (  1  ‘ 𝑥 )  ∈  ( 𝑥 𝐽 𝑥 )  ∧  ∀ 𝑦  ∈  𝑆 ∀ 𝑧  ∈  𝑆 ∀ 𝑓  ∈  ( 𝑥 𝐽 𝑦 ) ∀ 𝑔  ∈  ( 𝑦 𝐽 𝑧 ) ( 𝑔 ( 〈 𝑥 ,  𝑦 〉  ·  𝑧 ) 𝑓 )  ∈  ( 𝑥 𝐽 𝑧 ) ) ) ) ) |