| Step | Hyp | Ref | Expression | 
						
							| 1 |  | bj-imdirco.exa | ⊢ ( 𝜑  →  𝐴  ∈  𝑈 ) | 
						
							| 2 |  | bj-imdirco.exb | ⊢ ( 𝜑  →  𝐵  ∈  𝑉 ) | 
						
							| 3 |  | bj-imdirco.exc | ⊢ ( 𝜑  →  𝐶  ∈  𝑊 ) | 
						
							| 4 |  | bj-imdirco.arg1 | ⊢ ( 𝜑  →  𝑅  ⊆  ( 𝐴  ×  𝐵 ) ) | 
						
							| 5 |  | bj-imdirco.arg2 | ⊢ ( 𝜑  →  𝑆  ⊆  ( 𝐵  ×  𝐶 ) ) | 
						
							| 6 |  | imaco | ⊢ ( ( 𝑆  ∘  𝑅 )  “  𝑥 )  =  ( 𝑆  “  ( 𝑅  “  𝑥 ) ) | 
						
							| 7 | 6 | eqeq1i | ⊢ ( ( ( 𝑆  ∘  𝑅 )  “  𝑥 )  =  𝑧  ↔  ( 𝑆  “  ( 𝑅  “  𝑥 ) )  =  𝑧 ) | 
						
							| 8 | 7 | anbi2i | ⊢ ( ( ( 𝑥  ⊆  𝐴  ∧  𝑧  ⊆  𝐶 )  ∧  ( ( 𝑆  ∘  𝑅 )  “  𝑥 )  =  𝑧 )  ↔  ( ( 𝑥  ⊆  𝐴  ∧  𝑧  ⊆  𝐶 )  ∧  ( 𝑆  “  ( 𝑅  “  𝑥 ) )  =  𝑧 ) ) | 
						
							| 9 | 8 | a1i | ⊢ ( 𝜑  →  ( ( ( 𝑥  ⊆  𝐴  ∧  𝑧  ⊆  𝐶 )  ∧  ( ( 𝑆  ∘  𝑅 )  “  𝑥 )  =  𝑧 )  ↔  ( ( 𝑥  ⊆  𝐴  ∧  𝑧  ⊆  𝐶 )  ∧  ( 𝑆  “  ( 𝑅  “  𝑥 ) )  =  𝑧 ) ) ) | 
						
							| 10 | 1 2 | xpexd | ⊢ ( 𝜑  →  ( 𝐴  ×  𝐵 )  ∈  V ) | 
						
							| 11 | 10 4 | ssexd | ⊢ ( 𝜑  →  𝑅  ∈  V ) | 
						
							| 12 |  | imaexg | ⊢ ( 𝑅  ∈  V  →  ( 𝑅  “  𝑥 )  ∈  V ) | 
						
							| 13 | 11 12 | syl | ⊢ ( 𝜑  →  ( 𝑅  “  𝑥 )  ∈  V ) | 
						
							| 14 |  | imass1 | ⊢ ( 𝑅  ⊆  ( 𝐴  ×  𝐵 )  →  ( 𝑅  “  𝑥 )  ⊆  ( ( 𝐴  ×  𝐵 )  “  𝑥 ) ) | 
						
							| 15 |  | xpima | ⊢ ( ( 𝐴  ×  𝐵 )  “  𝑥 )  =  if ( ( 𝐴  ∩  𝑥 )  =  ∅ ,  ∅ ,  𝐵 ) | 
						
							| 16 |  | simpr | ⊢ ( ( ( 𝐴  ∩  𝑥 )  =  ∅  ∧  𝑢  ∈  ∅ )  →  𝑢  ∈  ∅ ) | 
						
							| 17 |  | simpr | ⊢ ( ( ¬  ( 𝐴  ∩  𝑥 )  =  ∅  ∧  𝑢  ∈  𝐵 )  →  𝑢  ∈  𝐵 ) | 
						
							| 18 | 16 17 | orim12i | ⊢ ( ( ( ( 𝐴  ∩  𝑥 )  =  ∅  ∧  𝑢  ∈  ∅ )  ∨  ( ¬  ( 𝐴  ∩  𝑥 )  =  ∅  ∧  𝑢  ∈  𝐵 ) )  →  ( 𝑢  ∈  ∅  ∨  𝑢  ∈  𝐵 ) ) | 
						
							| 19 |  | elif | ⊢ ( 𝑢  ∈  if ( ( 𝐴  ∩  𝑥 )  =  ∅ ,  ∅ ,  𝐵 )  ↔  ( ( ( 𝐴  ∩  𝑥 )  =  ∅  ∧  𝑢  ∈  ∅ )  ∨  ( ¬  ( 𝐴  ∩  𝑥 )  =  ∅  ∧  𝑢  ∈  𝐵 ) ) ) | 
						
							| 20 |  | elun | ⊢ ( 𝑢  ∈  ( ∅  ∪  𝐵 )  ↔  ( 𝑢  ∈  ∅  ∨  𝑢  ∈  𝐵 ) ) | 
						
							| 21 | 18 19 20 | 3imtr4i | ⊢ ( 𝑢  ∈  if ( ( 𝐴  ∩  𝑥 )  =  ∅ ,  ∅ ,  𝐵 )  →  𝑢  ∈  ( ∅  ∪  𝐵 ) ) | 
						
							| 22 | 21 | ssriv | ⊢ if ( ( 𝐴  ∩  𝑥 )  =  ∅ ,  ∅ ,  𝐵 )  ⊆  ( ∅  ∪  𝐵 ) | 
						
							| 23 |  | 0ss | ⊢ ∅  ⊆  𝐵 | 
						
							| 24 |  | ssid | ⊢ 𝐵  ⊆  𝐵 | 
						
							| 25 | 23 24 | unssi | ⊢ ( ∅  ∪  𝐵 )  ⊆  𝐵 | 
						
							| 26 | 22 25 | sstri | ⊢ if ( ( 𝐴  ∩  𝑥 )  =  ∅ ,  ∅ ,  𝐵 )  ⊆  𝐵 | 
						
							| 27 | 15 26 | eqsstri | ⊢ ( ( 𝐴  ×  𝐵 )  “  𝑥 )  ⊆  𝐵 | 
						
							| 28 | 14 27 | sstrdi | ⊢ ( 𝑅  ⊆  ( 𝐴  ×  𝐵 )  →  ( 𝑅  “  𝑥 )  ⊆  𝐵 ) | 
						
							| 29 | 4 28 | syl | ⊢ ( 𝜑  →  ( 𝑅  “  𝑥 )  ⊆  𝐵 ) | 
						
							| 30 |  | eqidd | ⊢ ( 𝜑  →  ( 𝑅  “  𝑥 )  =  ( 𝑅  “  𝑥 ) ) | 
						
							| 31 | 29 30 | jca | ⊢ ( 𝜑  →  ( ( 𝑅  “  𝑥 )  ⊆  𝐵  ∧  ( 𝑅  “  𝑥 )  =  ( 𝑅  “  𝑥 ) ) ) | 
						
							| 32 |  | sseq1 | ⊢ ( 𝑦  =  ( 𝑅  “  𝑥 )  →  ( 𝑦  ⊆  𝐵  ↔  ( 𝑅  “  𝑥 )  ⊆  𝐵 ) ) | 
						
							| 33 |  | eqeq2 | ⊢ ( 𝑦  =  ( 𝑅  “  𝑥 )  →  ( ( 𝑅  “  𝑥 )  =  𝑦  ↔  ( 𝑅  “  𝑥 )  =  ( 𝑅  “  𝑥 ) ) ) | 
						
							| 34 | 32 33 | anbi12d | ⊢ ( 𝑦  =  ( 𝑅  “  𝑥 )  →  ( ( 𝑦  ⊆  𝐵  ∧  ( 𝑅  “  𝑥 )  =  𝑦 )  ↔  ( ( 𝑅  “  𝑥 )  ⊆  𝐵  ∧  ( 𝑅  “  𝑥 )  =  ( 𝑅  “  𝑥 ) ) ) ) | 
						
							| 35 | 13 31 34 | spcedv | ⊢ ( 𝜑  →  ∃ 𝑦 ( 𝑦  ⊆  𝐵  ∧  ( 𝑅  “  𝑥 )  =  𝑦 ) ) | 
						
							| 36 | 35 | biantrurd | ⊢ ( 𝜑  →  ( ( 𝑆  “  ( 𝑅  “  𝑥 ) )  =  𝑧  ↔  ( ∃ 𝑦 ( 𝑦  ⊆  𝐵  ∧  ( 𝑅  “  𝑥 )  =  𝑦 )  ∧  ( 𝑆  “  ( 𝑅  “  𝑥 ) )  =  𝑧 ) ) ) | 
						
							| 37 |  | 19.41v | ⊢ ( ∃ 𝑦 ( ( 𝑦  ⊆  𝐵  ∧  ( 𝑅  “  𝑥 )  =  𝑦 )  ∧  ( 𝑆  “  ( 𝑅  “  𝑥 ) )  =  𝑧 )  ↔  ( ∃ 𝑦 ( 𝑦  ⊆  𝐵  ∧  ( 𝑅  “  𝑥 )  =  𝑦 )  ∧  ( 𝑆  “  ( 𝑅  “  𝑥 ) )  =  𝑧 ) ) | 
						
							| 38 |  | anass | ⊢ ( ( ( 𝑦  ⊆  𝐵  ∧  ( 𝑅  “  𝑥 )  =  𝑦 )  ∧  ( 𝑆  “  ( 𝑅  “  𝑥 ) )  =  𝑧 )  ↔  ( 𝑦  ⊆  𝐵  ∧  ( ( 𝑅  “  𝑥 )  =  𝑦  ∧  ( 𝑆  “  ( 𝑅  “  𝑥 ) )  =  𝑧 ) ) ) | 
						
							| 39 | 38 | exbii | ⊢ ( ∃ 𝑦 ( ( 𝑦  ⊆  𝐵  ∧  ( 𝑅  “  𝑥 )  =  𝑦 )  ∧  ( 𝑆  “  ( 𝑅  “  𝑥 ) )  =  𝑧 )  ↔  ∃ 𝑦 ( 𝑦  ⊆  𝐵  ∧  ( ( 𝑅  “  𝑥 )  =  𝑦  ∧  ( 𝑆  “  ( 𝑅  “  𝑥 ) )  =  𝑧 ) ) ) | 
						
							| 40 | 37 39 | bitr3i | ⊢ ( ( ∃ 𝑦 ( 𝑦  ⊆  𝐵  ∧  ( 𝑅  “  𝑥 )  =  𝑦 )  ∧  ( 𝑆  “  ( 𝑅  “  𝑥 ) )  =  𝑧 )  ↔  ∃ 𝑦 ( 𝑦  ⊆  𝐵  ∧  ( ( 𝑅  “  𝑥 )  =  𝑦  ∧  ( 𝑆  “  ( 𝑅  “  𝑥 ) )  =  𝑧 ) ) ) | 
						
							| 41 | 36 40 | bitrdi | ⊢ ( 𝜑  →  ( ( 𝑆  “  ( 𝑅  “  𝑥 ) )  =  𝑧  ↔  ∃ 𝑦 ( 𝑦  ⊆  𝐵  ∧  ( ( 𝑅  “  𝑥 )  =  𝑦  ∧  ( 𝑆  “  ( 𝑅  “  𝑥 ) )  =  𝑧 ) ) ) ) | 
						
							| 42 |  | imaeq2 | ⊢ ( ( 𝑅  “  𝑥 )  =  𝑦  →  ( 𝑆  “  ( 𝑅  “  𝑥 ) )  =  ( 𝑆  “  𝑦 ) ) | 
						
							| 43 | 42 | eqeq1d | ⊢ ( ( 𝑅  “  𝑥 )  =  𝑦  →  ( ( 𝑆  “  ( 𝑅  “  𝑥 ) )  =  𝑧  ↔  ( 𝑆  “  𝑦 )  =  𝑧 ) ) | 
						
							| 44 | 43 | pm5.32i | ⊢ ( ( ( 𝑅  “  𝑥 )  =  𝑦  ∧  ( 𝑆  “  ( 𝑅  “  𝑥 ) )  =  𝑧 )  ↔  ( ( 𝑅  “  𝑥 )  =  𝑦  ∧  ( 𝑆  “  𝑦 )  =  𝑧 ) ) | 
						
							| 45 | 44 | bianass | ⊢ ( ( 𝑦  ⊆  𝐵  ∧  ( ( 𝑅  “  𝑥 )  =  𝑦  ∧  ( 𝑆  “  ( 𝑅  “  𝑥 ) )  =  𝑧 ) )  ↔  ( ( 𝑦  ⊆  𝐵  ∧  ( 𝑅  “  𝑥 )  =  𝑦 )  ∧  ( 𝑆  “  𝑦 )  =  𝑧 ) ) | 
						
							| 46 | 45 | biancomi | ⊢ ( ( 𝑦  ⊆  𝐵  ∧  ( ( 𝑅  “  𝑥 )  =  𝑦  ∧  ( 𝑆  “  ( 𝑅  “  𝑥 ) )  =  𝑧 ) )  ↔  ( ( 𝑆  “  𝑦 )  =  𝑧  ∧  ( 𝑦  ⊆  𝐵  ∧  ( 𝑅  “  𝑥 )  =  𝑦 ) ) ) | 
						
							| 47 | 46 | exbii | ⊢ ( ∃ 𝑦 ( 𝑦  ⊆  𝐵  ∧  ( ( 𝑅  “  𝑥 )  =  𝑦  ∧  ( 𝑆  “  ( 𝑅  “  𝑥 ) )  =  𝑧 ) )  ↔  ∃ 𝑦 ( ( 𝑆  “  𝑦 )  =  𝑧  ∧  ( 𝑦  ⊆  𝐵  ∧  ( 𝑅  “  𝑥 )  =  𝑦 ) ) ) | 
						
							| 48 | 47 | a1i | ⊢ ( 𝜑  →  ( ∃ 𝑦 ( 𝑦  ⊆  𝐵  ∧  ( ( 𝑅  “  𝑥 )  =  𝑦  ∧  ( 𝑆  “  ( 𝑅  “  𝑥 ) )  =  𝑧 ) )  ↔  ∃ 𝑦 ( ( 𝑆  “  𝑦 )  =  𝑧  ∧  ( 𝑦  ⊆  𝐵  ∧  ( 𝑅  “  𝑥 )  =  𝑦 ) ) ) ) | 
						
							| 49 |  | pm4.24 | ⊢ ( 𝑦  ⊆  𝐵  ↔  ( 𝑦  ⊆  𝐵  ∧  𝑦  ⊆  𝐵 ) ) | 
						
							| 50 | 49 | anbi1i | ⊢ ( ( 𝑦  ⊆  𝐵  ∧  ( 𝑅  “  𝑥 )  =  𝑦 )  ↔  ( ( 𝑦  ⊆  𝐵  ∧  𝑦  ⊆  𝐵 )  ∧  ( 𝑅  “  𝑥 )  =  𝑦 ) ) | 
						
							| 51 |  | anass | ⊢ ( ( ( 𝑦  ⊆  𝐵  ∧  𝑦  ⊆  𝐵 )  ∧  ( 𝑅  “  𝑥 )  =  𝑦 )  ↔  ( 𝑦  ⊆  𝐵  ∧  ( 𝑦  ⊆  𝐵  ∧  ( 𝑅  “  𝑥 )  =  𝑦 ) ) ) | 
						
							| 52 | 50 51 | bitri | ⊢ ( ( 𝑦  ⊆  𝐵  ∧  ( 𝑅  “  𝑥 )  =  𝑦 )  ↔  ( 𝑦  ⊆  𝐵  ∧  ( 𝑦  ⊆  𝐵  ∧  ( 𝑅  “  𝑥 )  =  𝑦 ) ) ) | 
						
							| 53 | 52 | anbi2i | ⊢ ( ( ( 𝑆  “  𝑦 )  =  𝑧  ∧  ( 𝑦  ⊆  𝐵  ∧  ( 𝑅  “  𝑥 )  =  𝑦 ) )  ↔  ( ( 𝑆  “  𝑦 )  =  𝑧  ∧  ( 𝑦  ⊆  𝐵  ∧  ( 𝑦  ⊆  𝐵  ∧  ( 𝑅  “  𝑥 )  =  𝑦 ) ) ) ) | 
						
							| 54 |  | an12 | ⊢ ( ( ( 𝑆  “  𝑦 )  =  𝑧  ∧  ( 𝑦  ⊆  𝐵  ∧  ( 𝑦  ⊆  𝐵  ∧  ( 𝑅  “  𝑥 )  =  𝑦 ) ) )  ↔  ( 𝑦  ⊆  𝐵  ∧  ( ( 𝑆  “  𝑦 )  =  𝑧  ∧  ( 𝑦  ⊆  𝐵  ∧  ( 𝑅  “  𝑥 )  =  𝑦 ) ) ) ) | 
						
							| 55 | 53 54 | bitri | ⊢ ( ( ( 𝑆  “  𝑦 )  =  𝑧  ∧  ( 𝑦  ⊆  𝐵  ∧  ( 𝑅  “  𝑥 )  =  𝑦 ) )  ↔  ( 𝑦  ⊆  𝐵  ∧  ( ( 𝑆  “  𝑦 )  =  𝑧  ∧  ( 𝑦  ⊆  𝐵  ∧  ( 𝑅  “  𝑥 )  =  𝑦 ) ) ) ) | 
						
							| 56 | 55 | exbii | ⊢ ( ∃ 𝑦 ( ( 𝑆  “  𝑦 )  =  𝑧  ∧  ( 𝑦  ⊆  𝐵  ∧  ( 𝑅  “  𝑥 )  =  𝑦 ) )  ↔  ∃ 𝑦 ( 𝑦  ⊆  𝐵  ∧  ( ( 𝑆  “  𝑦 )  =  𝑧  ∧  ( 𝑦  ⊆  𝐵  ∧  ( 𝑅  “  𝑥 )  =  𝑦 ) ) ) ) | 
						
							| 57 | 56 | a1i | ⊢ ( 𝜑  →  ( ∃ 𝑦 ( ( 𝑆  “  𝑦 )  =  𝑧  ∧  ( 𝑦  ⊆  𝐵  ∧  ( 𝑅  “  𝑥 )  =  𝑦 ) )  ↔  ∃ 𝑦 ( 𝑦  ⊆  𝐵  ∧  ( ( 𝑆  “  𝑦 )  =  𝑧  ∧  ( 𝑦  ⊆  𝐵  ∧  ( 𝑅  “  𝑥 )  =  𝑦 ) ) ) ) ) | 
						
							| 58 | 41 48 57 | 3bitrd | ⊢ ( 𝜑  →  ( ( 𝑆  “  ( 𝑅  “  𝑥 ) )  =  𝑧  ↔  ∃ 𝑦 ( 𝑦  ⊆  𝐵  ∧  ( ( 𝑆  “  𝑦 )  =  𝑧  ∧  ( 𝑦  ⊆  𝐵  ∧  ( 𝑅  “  𝑥 )  =  𝑦 ) ) ) ) ) | 
						
							| 59 | 58 | anbi2d | ⊢ ( 𝜑  →  ( ( ( 𝑥  ⊆  𝐴  ∧  𝑧  ⊆  𝐶 )  ∧  ( 𝑆  “  ( 𝑅  “  𝑥 ) )  =  𝑧 )  ↔  ( ( 𝑥  ⊆  𝐴  ∧  𝑧  ⊆  𝐶 )  ∧  ∃ 𝑦 ( 𝑦  ⊆  𝐵  ∧  ( ( 𝑆  “  𝑦 )  =  𝑧  ∧  ( 𝑦  ⊆  𝐵  ∧  ( 𝑅  “  𝑥 )  =  𝑦 ) ) ) ) ) ) | 
						
							| 60 |  | 19.42v | ⊢ ( ∃ 𝑦 ( ( 𝑥  ⊆  𝐴  ∧  𝑧  ⊆  𝐶 )  ∧  ( 𝑦  ⊆  𝐵  ∧  ( ( 𝑆  “  𝑦 )  =  𝑧  ∧  ( 𝑦  ⊆  𝐵  ∧  ( 𝑅  “  𝑥 )  =  𝑦 ) ) ) )  ↔  ( ( 𝑥  ⊆  𝐴  ∧  𝑧  ⊆  𝐶 )  ∧  ∃ 𝑦 ( 𝑦  ⊆  𝐵  ∧  ( ( 𝑆  “  𝑦 )  =  𝑧  ∧  ( 𝑦  ⊆  𝐵  ∧  ( 𝑅  “  𝑥 )  =  𝑦 ) ) ) ) ) | 
						
							| 61 |  | anass | ⊢ ( ( ( 𝑥  ⊆  𝐴  ∧  𝑧  ⊆  𝐶 )  ∧  ( 𝑦  ⊆  𝐵  ∧  ( ( 𝑆  “  𝑦 )  =  𝑧  ∧  ( 𝑦  ⊆  𝐵  ∧  ( 𝑅  “  𝑥 )  =  𝑦 ) ) ) )  ↔  ( 𝑥  ⊆  𝐴  ∧  ( 𝑧  ⊆  𝐶  ∧  ( 𝑦  ⊆  𝐵  ∧  ( ( 𝑆  “  𝑦 )  =  𝑧  ∧  ( 𝑦  ⊆  𝐵  ∧  ( 𝑅  “  𝑥 )  =  𝑦 ) ) ) ) ) ) | 
						
							| 62 |  | ancom | ⊢ ( ( ( ( 𝑅  “  𝑥 )  =  𝑦  ∧  ( ( 𝑦  ⊆  𝐵  ∧  𝑧  ⊆  𝐶 )  ∧  ( 𝑆  “  𝑦 )  =  𝑧 ) )  ∧  𝑦  ⊆  𝐵 )  ↔  ( 𝑦  ⊆  𝐵  ∧  ( ( 𝑅  “  𝑥 )  =  𝑦  ∧  ( ( 𝑦  ⊆  𝐵  ∧  𝑧  ⊆  𝐶 )  ∧  ( 𝑆  “  𝑦 )  =  𝑧 ) ) ) ) | 
						
							| 63 | 62 | bianass | ⊢ ( ( 𝑥  ⊆  𝐴  ∧  ( ( ( 𝑅  “  𝑥 )  =  𝑦  ∧  ( ( 𝑦  ⊆  𝐵  ∧  𝑧  ⊆  𝐶 )  ∧  ( 𝑆  “  𝑦 )  =  𝑧 ) )  ∧  𝑦  ⊆  𝐵 ) )  ↔  ( ( 𝑥  ⊆  𝐴  ∧  𝑦  ⊆  𝐵 )  ∧  ( ( 𝑅  “  𝑥 )  =  𝑦  ∧  ( ( 𝑦  ⊆  𝐵  ∧  𝑧  ⊆  𝐶 )  ∧  ( 𝑆  “  𝑦 )  =  𝑧 ) ) ) ) | 
						
							| 64 |  | ancom | ⊢ ( ( ( ( ( 𝑦  ⊆  𝐵  ∧  𝑧  ⊆  𝐶 )  ∧  ( 𝑆  “  𝑦 )  =  𝑧 )  ∧  𝑦  ⊆  𝐵 )  ∧  ( 𝑅  “  𝑥 )  =  𝑦 )  ↔  ( ( 𝑅  “  𝑥 )  =  𝑦  ∧  ( ( ( 𝑦  ⊆  𝐵  ∧  𝑧  ⊆  𝐶 )  ∧  ( 𝑆  “  𝑦 )  =  𝑧 )  ∧  𝑦  ⊆  𝐵 ) ) ) | 
						
							| 65 |  | ancom | ⊢ ( ( 𝑧  ⊆  𝐶  ∧  𝑦  ⊆  𝐵 )  ↔  ( 𝑦  ⊆  𝐵  ∧  𝑧  ⊆  𝐶 ) ) | 
						
							| 66 | 65 | anbi1i | ⊢ ( ( ( 𝑧  ⊆  𝐶  ∧  𝑦  ⊆  𝐵 )  ∧  ( 𝑆  “  𝑦 )  =  𝑧 )  ↔  ( ( 𝑦  ⊆  𝐵  ∧  𝑧  ⊆  𝐶 )  ∧  ( 𝑆  “  𝑦 )  =  𝑧 ) ) | 
						
							| 67 | 66 | anbi1i | ⊢ ( ( ( ( 𝑧  ⊆  𝐶  ∧  𝑦  ⊆  𝐵 )  ∧  ( 𝑆  “  𝑦 )  =  𝑧 )  ∧  ( 𝑦  ⊆  𝐵  ∧  ( 𝑅  “  𝑥 )  =  𝑦 ) )  ↔  ( ( ( 𝑦  ⊆  𝐵  ∧  𝑧  ⊆  𝐶 )  ∧  ( 𝑆  “  𝑦 )  =  𝑧 )  ∧  ( 𝑦  ⊆  𝐵  ∧  ( 𝑅  “  𝑥 )  =  𝑦 ) ) ) | 
						
							| 68 |  | biid | ⊢ ( ( 𝑦  ⊆  𝐵  ∧  ( ( 𝑆  “  𝑦 )  =  𝑧  ∧  ( 𝑦  ⊆  𝐵  ∧  ( 𝑅  “  𝑥 )  =  𝑦 ) ) )  ↔  ( 𝑦  ⊆  𝐵  ∧  ( ( 𝑆  “  𝑦 )  =  𝑧  ∧  ( 𝑦  ⊆  𝐵  ∧  ( 𝑅  “  𝑥 )  =  𝑦 ) ) ) ) | 
						
							| 69 | 68 | bianass | ⊢ ( ( 𝑧  ⊆  𝐶  ∧  ( 𝑦  ⊆  𝐵  ∧  ( ( 𝑆  “  𝑦 )  =  𝑧  ∧  ( 𝑦  ⊆  𝐵  ∧  ( 𝑅  “  𝑥 )  =  𝑦 ) ) ) )  ↔  ( ( 𝑧  ⊆  𝐶  ∧  𝑦  ⊆  𝐵 )  ∧  ( ( 𝑆  “  𝑦 )  =  𝑧  ∧  ( 𝑦  ⊆  𝐵  ∧  ( 𝑅  “  𝑥 )  =  𝑦 ) ) ) ) | 
						
							| 70 |  | anass | ⊢ ( ( ( ( 𝑧  ⊆  𝐶  ∧  𝑦  ⊆  𝐵 )  ∧  ( 𝑆  “  𝑦 )  =  𝑧 )  ∧  ( 𝑦  ⊆  𝐵  ∧  ( 𝑅  “  𝑥 )  =  𝑦 ) )  ↔  ( ( 𝑧  ⊆  𝐶  ∧  𝑦  ⊆  𝐵 )  ∧  ( ( 𝑆  “  𝑦 )  =  𝑧  ∧  ( 𝑦  ⊆  𝐵  ∧  ( 𝑅  “  𝑥 )  =  𝑦 ) ) ) ) | 
						
							| 71 | 69 70 | bitr4i | ⊢ ( ( 𝑧  ⊆  𝐶  ∧  ( 𝑦  ⊆  𝐵  ∧  ( ( 𝑆  “  𝑦 )  =  𝑧  ∧  ( 𝑦  ⊆  𝐵  ∧  ( 𝑅  “  𝑥 )  =  𝑦 ) ) ) )  ↔  ( ( ( 𝑧  ⊆  𝐶  ∧  𝑦  ⊆  𝐵 )  ∧  ( 𝑆  “  𝑦 )  =  𝑧 )  ∧  ( 𝑦  ⊆  𝐵  ∧  ( 𝑅  “  𝑥 )  =  𝑦 ) ) ) | 
						
							| 72 |  | anass | ⊢ ( ( ( ( ( 𝑦  ⊆  𝐵  ∧  𝑧  ⊆  𝐶 )  ∧  ( 𝑆  “  𝑦 )  =  𝑧 )  ∧  𝑦  ⊆  𝐵 )  ∧  ( 𝑅  “  𝑥 )  =  𝑦 )  ↔  ( ( ( 𝑦  ⊆  𝐵  ∧  𝑧  ⊆  𝐶 )  ∧  ( 𝑆  “  𝑦 )  =  𝑧 )  ∧  ( 𝑦  ⊆  𝐵  ∧  ( 𝑅  “  𝑥 )  =  𝑦 ) ) ) | 
						
							| 73 | 67 71 72 | 3bitr4i | ⊢ ( ( 𝑧  ⊆  𝐶  ∧  ( 𝑦  ⊆  𝐵  ∧  ( ( 𝑆  “  𝑦 )  =  𝑧  ∧  ( 𝑦  ⊆  𝐵  ∧  ( 𝑅  “  𝑥 )  =  𝑦 ) ) ) )  ↔  ( ( ( ( 𝑦  ⊆  𝐵  ∧  𝑧  ⊆  𝐶 )  ∧  ( 𝑆  “  𝑦 )  =  𝑧 )  ∧  𝑦  ⊆  𝐵 )  ∧  ( 𝑅  “  𝑥 )  =  𝑦 ) ) | 
						
							| 74 |  | anass | ⊢ ( ( ( ( 𝑅  “  𝑥 )  =  𝑦  ∧  ( ( 𝑦  ⊆  𝐵  ∧  𝑧  ⊆  𝐶 )  ∧  ( 𝑆  “  𝑦 )  =  𝑧 ) )  ∧  𝑦  ⊆  𝐵 )  ↔  ( ( 𝑅  “  𝑥 )  =  𝑦  ∧  ( ( ( 𝑦  ⊆  𝐵  ∧  𝑧  ⊆  𝐶 )  ∧  ( 𝑆  “  𝑦 )  =  𝑧 )  ∧  𝑦  ⊆  𝐵 ) ) ) | 
						
							| 75 | 64 73 74 | 3bitr4i | ⊢ ( ( 𝑧  ⊆  𝐶  ∧  ( 𝑦  ⊆  𝐵  ∧  ( ( 𝑆  “  𝑦 )  =  𝑧  ∧  ( 𝑦  ⊆  𝐵  ∧  ( 𝑅  “  𝑥 )  =  𝑦 ) ) ) )  ↔  ( ( ( 𝑅  “  𝑥 )  =  𝑦  ∧  ( ( 𝑦  ⊆  𝐵  ∧  𝑧  ⊆  𝐶 )  ∧  ( 𝑆  “  𝑦 )  =  𝑧 ) )  ∧  𝑦  ⊆  𝐵 ) ) | 
						
							| 76 | 75 | anbi2i | ⊢ ( ( 𝑥  ⊆  𝐴  ∧  ( 𝑧  ⊆  𝐶  ∧  ( 𝑦  ⊆  𝐵  ∧  ( ( 𝑆  “  𝑦 )  =  𝑧  ∧  ( 𝑦  ⊆  𝐵  ∧  ( 𝑅  “  𝑥 )  =  𝑦 ) ) ) ) )  ↔  ( 𝑥  ⊆  𝐴  ∧  ( ( ( 𝑅  “  𝑥 )  =  𝑦  ∧  ( ( 𝑦  ⊆  𝐵  ∧  𝑧  ⊆  𝐶 )  ∧  ( 𝑆  “  𝑦 )  =  𝑧 ) )  ∧  𝑦  ⊆  𝐵 ) ) ) | 
						
							| 77 |  | anass | ⊢ ( ( ( ( 𝑥  ⊆  𝐴  ∧  𝑦  ⊆  𝐵 )  ∧  ( 𝑅  “  𝑥 )  =  𝑦 )  ∧  ( ( 𝑦  ⊆  𝐵  ∧  𝑧  ⊆  𝐶 )  ∧  ( 𝑆  “  𝑦 )  =  𝑧 ) )  ↔  ( ( 𝑥  ⊆  𝐴  ∧  𝑦  ⊆  𝐵 )  ∧  ( ( 𝑅  “  𝑥 )  =  𝑦  ∧  ( ( 𝑦  ⊆  𝐵  ∧  𝑧  ⊆  𝐶 )  ∧  ( 𝑆  “  𝑦 )  =  𝑧 ) ) ) ) | 
						
							| 78 | 63 76 77 | 3bitr4i | ⊢ ( ( 𝑥  ⊆  𝐴  ∧  ( 𝑧  ⊆  𝐶  ∧  ( 𝑦  ⊆  𝐵  ∧  ( ( 𝑆  “  𝑦 )  =  𝑧  ∧  ( 𝑦  ⊆  𝐵  ∧  ( 𝑅  “  𝑥 )  =  𝑦 ) ) ) ) )  ↔  ( ( ( 𝑥  ⊆  𝐴  ∧  𝑦  ⊆  𝐵 )  ∧  ( 𝑅  “  𝑥 )  =  𝑦 )  ∧  ( ( 𝑦  ⊆  𝐵  ∧  𝑧  ⊆  𝐶 )  ∧  ( 𝑆  “  𝑦 )  =  𝑧 ) ) ) | 
						
							| 79 | 61 78 | bitri | ⊢ ( ( ( 𝑥  ⊆  𝐴  ∧  𝑧  ⊆  𝐶 )  ∧  ( 𝑦  ⊆  𝐵  ∧  ( ( 𝑆  “  𝑦 )  =  𝑧  ∧  ( 𝑦  ⊆  𝐵  ∧  ( 𝑅  “  𝑥 )  =  𝑦 ) ) ) )  ↔  ( ( ( 𝑥  ⊆  𝐴  ∧  𝑦  ⊆  𝐵 )  ∧  ( 𝑅  “  𝑥 )  =  𝑦 )  ∧  ( ( 𝑦  ⊆  𝐵  ∧  𝑧  ⊆  𝐶 )  ∧  ( 𝑆  “  𝑦 )  =  𝑧 ) ) ) | 
						
							| 80 | 79 | exbii | ⊢ ( ∃ 𝑦 ( ( 𝑥  ⊆  𝐴  ∧  𝑧  ⊆  𝐶 )  ∧  ( 𝑦  ⊆  𝐵  ∧  ( ( 𝑆  “  𝑦 )  =  𝑧  ∧  ( 𝑦  ⊆  𝐵  ∧  ( 𝑅  “  𝑥 )  =  𝑦 ) ) ) )  ↔  ∃ 𝑦 ( ( ( 𝑥  ⊆  𝐴  ∧  𝑦  ⊆  𝐵 )  ∧  ( 𝑅  “  𝑥 )  =  𝑦 )  ∧  ( ( 𝑦  ⊆  𝐵  ∧  𝑧  ⊆  𝐶 )  ∧  ( 𝑆  “  𝑦 )  =  𝑧 ) ) ) | 
						
							| 81 | 60 80 | bitr3i | ⊢ ( ( ( 𝑥  ⊆  𝐴  ∧  𝑧  ⊆  𝐶 )  ∧  ∃ 𝑦 ( 𝑦  ⊆  𝐵  ∧  ( ( 𝑆  “  𝑦 )  =  𝑧  ∧  ( 𝑦  ⊆  𝐵  ∧  ( 𝑅  “  𝑥 )  =  𝑦 ) ) ) )  ↔  ∃ 𝑦 ( ( ( 𝑥  ⊆  𝐴  ∧  𝑦  ⊆  𝐵 )  ∧  ( 𝑅  “  𝑥 )  =  𝑦 )  ∧  ( ( 𝑦  ⊆  𝐵  ∧  𝑧  ⊆  𝐶 )  ∧  ( 𝑆  “  𝑦 )  =  𝑧 ) ) ) | 
						
							| 82 | 81 | a1i | ⊢ ( 𝜑  →  ( ( ( 𝑥  ⊆  𝐴  ∧  𝑧  ⊆  𝐶 )  ∧  ∃ 𝑦 ( 𝑦  ⊆  𝐵  ∧  ( ( 𝑆  “  𝑦 )  =  𝑧  ∧  ( 𝑦  ⊆  𝐵  ∧  ( 𝑅  “  𝑥 )  =  𝑦 ) ) ) )  ↔  ∃ 𝑦 ( ( ( 𝑥  ⊆  𝐴  ∧  𝑦  ⊆  𝐵 )  ∧  ( 𝑅  “  𝑥 )  =  𝑦 )  ∧  ( ( 𝑦  ⊆  𝐵  ∧  𝑧  ⊆  𝐶 )  ∧  ( 𝑆  “  𝑦 )  =  𝑧 ) ) ) ) | 
						
							| 83 | 9 59 82 | 3bitrd | ⊢ ( 𝜑  →  ( ( ( 𝑥  ⊆  𝐴  ∧  𝑧  ⊆  𝐶 )  ∧  ( ( 𝑆  ∘  𝑅 )  “  𝑥 )  =  𝑧 )  ↔  ∃ 𝑦 ( ( ( 𝑥  ⊆  𝐴  ∧  𝑦  ⊆  𝐵 )  ∧  ( 𝑅  “  𝑥 )  =  𝑦 )  ∧  ( ( 𝑦  ⊆  𝐵  ∧  𝑧  ⊆  𝐶 )  ∧  ( 𝑆  “  𝑦 )  =  𝑧 ) ) ) ) | 
						
							| 84 | 83 | opabbidv | ⊢ ( 𝜑  →  { 〈 𝑥 ,  𝑧 〉  ∣  ( ( 𝑥  ⊆  𝐴  ∧  𝑧  ⊆  𝐶 )  ∧  ( ( 𝑆  ∘  𝑅 )  “  𝑥 )  =  𝑧 ) }  =  { 〈 𝑥 ,  𝑧 〉  ∣  ∃ 𝑦 ( ( ( 𝑥  ⊆  𝐴  ∧  𝑦  ⊆  𝐵 )  ∧  ( 𝑅  “  𝑥 )  =  𝑦 )  ∧  ( ( 𝑦  ⊆  𝐵  ∧  𝑧  ⊆  𝐶 )  ∧  ( 𝑆  “  𝑦 )  =  𝑧 ) ) } ) | 
						
							| 85 |  | bj-opabco | ⊢ ( { 〈 𝑦 ,  𝑧 〉  ∣  ( ( 𝑦  ⊆  𝐵  ∧  𝑧  ⊆  𝐶 )  ∧  ( 𝑆  “  𝑦 )  =  𝑧 ) }  ∘  { 〈 𝑥 ,  𝑦 〉  ∣  ( ( 𝑥  ⊆  𝐴  ∧  𝑦  ⊆  𝐵 )  ∧  ( 𝑅  “  𝑥 )  =  𝑦 ) } )  =  { 〈 𝑥 ,  𝑧 〉  ∣  ∃ 𝑦 ( ( ( 𝑥  ⊆  𝐴  ∧  𝑦  ⊆  𝐵 )  ∧  ( 𝑅  “  𝑥 )  =  𝑦 )  ∧  ( ( 𝑦  ⊆  𝐵  ∧  𝑧  ⊆  𝐶 )  ∧  ( 𝑆  “  𝑦 )  =  𝑧 ) ) } | 
						
							| 86 | 84 85 | eqtr4di | ⊢ ( 𝜑  →  { 〈 𝑥 ,  𝑧 〉  ∣  ( ( 𝑥  ⊆  𝐴  ∧  𝑧  ⊆  𝐶 )  ∧  ( ( 𝑆  ∘  𝑅 )  “  𝑥 )  =  𝑧 ) }  =  ( { 〈 𝑦 ,  𝑧 〉  ∣  ( ( 𝑦  ⊆  𝐵  ∧  𝑧  ⊆  𝐶 )  ∧  ( 𝑆  “  𝑦 )  =  𝑧 ) }  ∘  { 〈 𝑥 ,  𝑦 〉  ∣  ( ( 𝑥  ⊆  𝐴  ∧  𝑦  ⊆  𝐵 )  ∧  ( 𝑅  “  𝑥 )  =  𝑦 ) } ) ) | 
						
							| 87 | 5 4 | coss12d | ⊢ ( 𝜑  →  ( 𝑆  ∘  𝑅 )  ⊆  ( ( 𝐵  ×  𝐶 )  ∘  ( 𝐴  ×  𝐵 ) ) ) | 
						
							| 88 |  | bj-xpcossxp | ⊢ ( ( 𝐵  ×  𝐶 )  ∘  ( 𝐴  ×  𝐵 ) )  ⊆  ( 𝐴  ×  𝐶 ) | 
						
							| 89 | 87 88 | sstrdi | ⊢ ( 𝜑  →  ( 𝑆  ∘  𝑅 )  ⊆  ( 𝐴  ×  𝐶 ) ) | 
						
							| 90 | 1 3 89 | bj-imdirval2 | ⊢ ( 𝜑  →  ( ( 𝐴 𝒫* 𝐶 ) ‘ ( 𝑆  ∘  𝑅 ) )  =  { 〈 𝑥 ,  𝑧 〉  ∣  ( ( 𝑥  ⊆  𝐴  ∧  𝑧  ⊆  𝐶 )  ∧  ( ( 𝑆  ∘  𝑅 )  “  𝑥 )  =  𝑧 ) } ) | 
						
							| 91 | 2 3 5 | bj-imdirval2 | ⊢ ( 𝜑  →  ( ( 𝐵 𝒫* 𝐶 ) ‘ 𝑆 )  =  { 〈 𝑦 ,  𝑧 〉  ∣  ( ( 𝑦  ⊆  𝐵  ∧  𝑧  ⊆  𝐶 )  ∧  ( 𝑆  “  𝑦 )  =  𝑧 ) } ) | 
						
							| 92 | 1 2 4 | bj-imdirval2 | ⊢ ( 𝜑  →  ( ( 𝐴 𝒫* 𝐵 ) ‘ 𝑅 )  =  { 〈 𝑥 ,  𝑦 〉  ∣  ( ( 𝑥  ⊆  𝐴  ∧  𝑦  ⊆  𝐵 )  ∧  ( 𝑅  “  𝑥 )  =  𝑦 ) } ) | 
						
							| 93 | 91 92 | coeq12d | ⊢ ( 𝜑  →  ( ( ( 𝐵 𝒫* 𝐶 ) ‘ 𝑆 )  ∘  ( ( 𝐴 𝒫* 𝐵 ) ‘ 𝑅 ) )  =  ( { 〈 𝑦 ,  𝑧 〉  ∣  ( ( 𝑦  ⊆  𝐵  ∧  𝑧  ⊆  𝐶 )  ∧  ( 𝑆  “  𝑦 )  =  𝑧 ) }  ∘  { 〈 𝑥 ,  𝑦 〉  ∣  ( ( 𝑥  ⊆  𝐴  ∧  𝑦  ⊆  𝐵 )  ∧  ( 𝑅  “  𝑥 )  =  𝑦 ) } ) ) | 
						
							| 94 | 86 90 93 | 3eqtr4d | ⊢ ( 𝜑  →  ( ( 𝐴 𝒫* 𝐶 ) ‘ ( 𝑆  ∘  𝑅 ) )  =  ( ( ( 𝐵 𝒫* 𝐶 ) ‘ 𝑆 )  ∘  ( ( 𝐴 𝒫* 𝐵 ) ‘ 𝑅 ) ) ) |