| Step | Hyp | Ref | Expression | 
						
							| 1 |  | mstaval.r | ⊢ 𝑅  =  ( mStRed ‘ 𝑇 ) | 
						
							| 2 |  | mstaval.s | ⊢ 𝑆  =  ( mStat ‘ 𝑇 ) | 
						
							| 3 |  | eqid | ⊢ ( mPreSt ‘ 𝑇 )  =  ( mPreSt ‘ 𝑇 ) | 
						
							| 4 | 3 1 | msrf | ⊢ 𝑅 : ( mPreSt ‘ 𝑇 ) ⟶ ( mPreSt ‘ 𝑇 ) | 
						
							| 5 |  | ffn | ⊢ ( 𝑅 : ( mPreSt ‘ 𝑇 ) ⟶ ( mPreSt ‘ 𝑇 )  →  𝑅  Fn  ( mPreSt ‘ 𝑇 ) ) | 
						
							| 6 |  | fvelrnb | ⊢ ( 𝑅  Fn  ( mPreSt ‘ 𝑇 )  →  ( 𝑋  ∈  ran  𝑅  ↔  ∃ 𝑠  ∈  ( mPreSt ‘ 𝑇 ) ( 𝑅 ‘ 𝑠 )  =  𝑋 ) ) | 
						
							| 7 | 4 5 6 | mp2b | ⊢ ( 𝑋  ∈  ran  𝑅  ↔  ∃ 𝑠  ∈  ( mPreSt ‘ 𝑇 ) ( 𝑅 ‘ 𝑠 )  =  𝑋 ) | 
						
							| 8 | 3 | mpst123 | ⊢ ( 𝑠  ∈  ( mPreSt ‘ 𝑇 )  →  𝑠  =  〈 ( 1st  ‘ ( 1st  ‘ 𝑠 ) ) ,  ( 2nd  ‘ ( 1st  ‘ 𝑠 ) ) ,  ( 2nd  ‘ 𝑠 ) 〉 ) | 
						
							| 9 | 8 | fveq2d | ⊢ ( 𝑠  ∈  ( mPreSt ‘ 𝑇 )  →  ( 𝑅 ‘ 𝑠 )  =  ( 𝑅 ‘ 〈 ( 1st  ‘ ( 1st  ‘ 𝑠 ) ) ,  ( 2nd  ‘ ( 1st  ‘ 𝑠 ) ) ,  ( 2nd  ‘ 𝑠 ) 〉 ) ) | 
						
							| 10 |  | id | ⊢ ( 𝑠  ∈  ( mPreSt ‘ 𝑇 )  →  𝑠  ∈  ( mPreSt ‘ 𝑇 ) ) | 
						
							| 11 | 8 10 | eqeltrrd | ⊢ ( 𝑠  ∈  ( mPreSt ‘ 𝑇 )  →  〈 ( 1st  ‘ ( 1st  ‘ 𝑠 ) ) ,  ( 2nd  ‘ ( 1st  ‘ 𝑠 ) ) ,  ( 2nd  ‘ 𝑠 ) 〉  ∈  ( mPreSt ‘ 𝑇 ) ) | 
						
							| 12 |  | eqid | ⊢ ( mVars ‘ 𝑇 )  =  ( mVars ‘ 𝑇 ) | 
						
							| 13 |  | eqid | ⊢ ∪  ( ( mVars ‘ 𝑇 )  “  ( ( 2nd  ‘ ( 1st  ‘ 𝑠 ) )  ∪  { ( 2nd  ‘ 𝑠 ) } ) )  =  ∪  ( ( mVars ‘ 𝑇 )  “  ( ( 2nd  ‘ ( 1st  ‘ 𝑠 ) )  ∪  { ( 2nd  ‘ 𝑠 ) } ) ) | 
						
							| 14 | 12 3 1 13 | msrval | ⊢ ( 〈 ( 1st  ‘ ( 1st  ‘ 𝑠 ) ) ,  ( 2nd  ‘ ( 1st  ‘ 𝑠 ) ) ,  ( 2nd  ‘ 𝑠 ) 〉  ∈  ( mPreSt ‘ 𝑇 )  →  ( 𝑅 ‘ 〈 ( 1st  ‘ ( 1st  ‘ 𝑠 ) ) ,  ( 2nd  ‘ ( 1st  ‘ 𝑠 ) ) ,  ( 2nd  ‘ 𝑠 ) 〉 )  =  〈 ( ( 1st  ‘ ( 1st  ‘ 𝑠 ) )  ∩  ( ∪  ( ( mVars ‘ 𝑇 )  “  ( ( 2nd  ‘ ( 1st  ‘ 𝑠 ) )  ∪  { ( 2nd  ‘ 𝑠 ) } ) )  ×  ∪  ( ( mVars ‘ 𝑇 )  “  ( ( 2nd  ‘ ( 1st  ‘ 𝑠 ) )  ∪  { ( 2nd  ‘ 𝑠 ) } ) ) ) ) ,  ( 2nd  ‘ ( 1st  ‘ 𝑠 ) ) ,  ( 2nd  ‘ 𝑠 ) 〉 ) | 
						
							| 15 | 11 14 | syl | ⊢ ( 𝑠  ∈  ( mPreSt ‘ 𝑇 )  →  ( 𝑅 ‘ 〈 ( 1st  ‘ ( 1st  ‘ 𝑠 ) ) ,  ( 2nd  ‘ ( 1st  ‘ 𝑠 ) ) ,  ( 2nd  ‘ 𝑠 ) 〉 )  =  〈 ( ( 1st  ‘ ( 1st  ‘ 𝑠 ) )  ∩  ( ∪  ( ( mVars ‘ 𝑇 )  “  ( ( 2nd  ‘ ( 1st  ‘ 𝑠 ) )  ∪  { ( 2nd  ‘ 𝑠 ) } ) )  ×  ∪  ( ( mVars ‘ 𝑇 )  “  ( ( 2nd  ‘ ( 1st  ‘ 𝑠 ) )  ∪  { ( 2nd  ‘ 𝑠 ) } ) ) ) ) ,  ( 2nd  ‘ ( 1st  ‘ 𝑠 ) ) ,  ( 2nd  ‘ 𝑠 ) 〉 ) | 
						
							| 16 | 9 15 | eqtrd | ⊢ ( 𝑠  ∈  ( mPreSt ‘ 𝑇 )  →  ( 𝑅 ‘ 𝑠 )  =  〈 ( ( 1st  ‘ ( 1st  ‘ 𝑠 ) )  ∩  ( ∪  ( ( mVars ‘ 𝑇 )  “  ( ( 2nd  ‘ ( 1st  ‘ 𝑠 ) )  ∪  { ( 2nd  ‘ 𝑠 ) } ) )  ×  ∪  ( ( mVars ‘ 𝑇 )  “  ( ( 2nd  ‘ ( 1st  ‘ 𝑠 ) )  ∪  { ( 2nd  ‘ 𝑠 ) } ) ) ) ) ,  ( 2nd  ‘ ( 1st  ‘ 𝑠 ) ) ,  ( 2nd  ‘ 𝑠 ) 〉 ) | 
						
							| 17 | 4 | ffvelcdmi | ⊢ ( 𝑠  ∈  ( mPreSt ‘ 𝑇 )  →  ( 𝑅 ‘ 𝑠 )  ∈  ( mPreSt ‘ 𝑇 ) ) | 
						
							| 18 | 16 17 | eqeltrrd | ⊢ ( 𝑠  ∈  ( mPreSt ‘ 𝑇 )  →  〈 ( ( 1st  ‘ ( 1st  ‘ 𝑠 ) )  ∩  ( ∪  ( ( mVars ‘ 𝑇 )  “  ( ( 2nd  ‘ ( 1st  ‘ 𝑠 ) )  ∪  { ( 2nd  ‘ 𝑠 ) } ) )  ×  ∪  ( ( mVars ‘ 𝑇 )  “  ( ( 2nd  ‘ ( 1st  ‘ 𝑠 ) )  ∪  { ( 2nd  ‘ 𝑠 ) } ) ) ) ) ,  ( 2nd  ‘ ( 1st  ‘ 𝑠 ) ) ,  ( 2nd  ‘ 𝑠 ) 〉  ∈  ( mPreSt ‘ 𝑇 ) ) | 
						
							| 19 | 12 3 1 13 | msrval | ⊢ ( 〈 ( ( 1st  ‘ ( 1st  ‘ 𝑠 ) )  ∩  ( ∪  ( ( mVars ‘ 𝑇 )  “  ( ( 2nd  ‘ ( 1st  ‘ 𝑠 ) )  ∪  { ( 2nd  ‘ 𝑠 ) } ) )  ×  ∪  ( ( mVars ‘ 𝑇 )  “  ( ( 2nd  ‘ ( 1st  ‘ 𝑠 ) )  ∪  { ( 2nd  ‘ 𝑠 ) } ) ) ) ) ,  ( 2nd  ‘ ( 1st  ‘ 𝑠 ) ) ,  ( 2nd  ‘ 𝑠 ) 〉  ∈  ( mPreSt ‘ 𝑇 )  →  ( 𝑅 ‘ 〈 ( ( 1st  ‘ ( 1st  ‘ 𝑠 ) )  ∩  ( ∪  ( ( mVars ‘ 𝑇 )  “  ( ( 2nd  ‘ ( 1st  ‘ 𝑠 ) )  ∪  { ( 2nd  ‘ 𝑠 ) } ) )  ×  ∪  ( ( mVars ‘ 𝑇 )  “  ( ( 2nd  ‘ ( 1st  ‘ 𝑠 ) )  ∪  { ( 2nd  ‘ 𝑠 ) } ) ) ) ) ,  ( 2nd  ‘ ( 1st  ‘ 𝑠 ) ) ,  ( 2nd  ‘ 𝑠 ) 〉 )  =  〈 ( ( ( 1st  ‘ ( 1st  ‘ 𝑠 ) )  ∩  ( ∪  ( ( mVars ‘ 𝑇 )  “  ( ( 2nd  ‘ ( 1st  ‘ 𝑠 ) )  ∪  { ( 2nd  ‘ 𝑠 ) } ) )  ×  ∪  ( ( mVars ‘ 𝑇 )  “  ( ( 2nd  ‘ ( 1st  ‘ 𝑠 ) )  ∪  { ( 2nd  ‘ 𝑠 ) } ) ) ) )  ∩  ( ∪  ( ( mVars ‘ 𝑇 )  “  ( ( 2nd  ‘ ( 1st  ‘ 𝑠 ) )  ∪  { ( 2nd  ‘ 𝑠 ) } ) )  ×  ∪  ( ( mVars ‘ 𝑇 )  “  ( ( 2nd  ‘ ( 1st  ‘ 𝑠 ) )  ∪  { ( 2nd  ‘ 𝑠 ) } ) ) ) ) ,  ( 2nd  ‘ ( 1st  ‘ 𝑠 ) ) ,  ( 2nd  ‘ 𝑠 ) 〉 ) | 
						
							| 20 | 18 19 | syl | ⊢ ( 𝑠  ∈  ( mPreSt ‘ 𝑇 )  →  ( 𝑅 ‘ 〈 ( ( 1st  ‘ ( 1st  ‘ 𝑠 ) )  ∩  ( ∪  ( ( mVars ‘ 𝑇 )  “  ( ( 2nd  ‘ ( 1st  ‘ 𝑠 ) )  ∪  { ( 2nd  ‘ 𝑠 ) } ) )  ×  ∪  ( ( mVars ‘ 𝑇 )  “  ( ( 2nd  ‘ ( 1st  ‘ 𝑠 ) )  ∪  { ( 2nd  ‘ 𝑠 ) } ) ) ) ) ,  ( 2nd  ‘ ( 1st  ‘ 𝑠 ) ) ,  ( 2nd  ‘ 𝑠 ) 〉 )  =  〈 ( ( ( 1st  ‘ ( 1st  ‘ 𝑠 ) )  ∩  ( ∪  ( ( mVars ‘ 𝑇 )  “  ( ( 2nd  ‘ ( 1st  ‘ 𝑠 ) )  ∪  { ( 2nd  ‘ 𝑠 ) } ) )  ×  ∪  ( ( mVars ‘ 𝑇 )  “  ( ( 2nd  ‘ ( 1st  ‘ 𝑠 ) )  ∪  { ( 2nd  ‘ 𝑠 ) } ) ) ) )  ∩  ( ∪  ( ( mVars ‘ 𝑇 )  “  ( ( 2nd  ‘ ( 1st  ‘ 𝑠 ) )  ∪  { ( 2nd  ‘ 𝑠 ) } ) )  ×  ∪  ( ( mVars ‘ 𝑇 )  “  ( ( 2nd  ‘ ( 1st  ‘ 𝑠 ) )  ∪  { ( 2nd  ‘ 𝑠 ) } ) ) ) ) ,  ( 2nd  ‘ ( 1st  ‘ 𝑠 ) ) ,  ( 2nd  ‘ 𝑠 ) 〉 ) | 
						
							| 21 |  | inass | ⊢ ( ( ( 1st  ‘ ( 1st  ‘ 𝑠 ) )  ∩  ( ∪  ( ( mVars ‘ 𝑇 )  “  ( ( 2nd  ‘ ( 1st  ‘ 𝑠 ) )  ∪  { ( 2nd  ‘ 𝑠 ) } ) )  ×  ∪  ( ( mVars ‘ 𝑇 )  “  ( ( 2nd  ‘ ( 1st  ‘ 𝑠 ) )  ∪  { ( 2nd  ‘ 𝑠 ) } ) ) ) )  ∩  ( ∪  ( ( mVars ‘ 𝑇 )  “  ( ( 2nd  ‘ ( 1st  ‘ 𝑠 ) )  ∪  { ( 2nd  ‘ 𝑠 ) } ) )  ×  ∪  ( ( mVars ‘ 𝑇 )  “  ( ( 2nd  ‘ ( 1st  ‘ 𝑠 ) )  ∪  { ( 2nd  ‘ 𝑠 ) } ) ) ) )  =  ( ( 1st  ‘ ( 1st  ‘ 𝑠 ) )  ∩  ( ( ∪  ( ( mVars ‘ 𝑇 )  “  ( ( 2nd  ‘ ( 1st  ‘ 𝑠 ) )  ∪  { ( 2nd  ‘ 𝑠 ) } ) )  ×  ∪  ( ( mVars ‘ 𝑇 )  “  ( ( 2nd  ‘ ( 1st  ‘ 𝑠 ) )  ∪  { ( 2nd  ‘ 𝑠 ) } ) ) )  ∩  ( ∪  ( ( mVars ‘ 𝑇 )  “  ( ( 2nd  ‘ ( 1st  ‘ 𝑠 ) )  ∪  { ( 2nd  ‘ 𝑠 ) } ) )  ×  ∪  ( ( mVars ‘ 𝑇 )  “  ( ( 2nd  ‘ ( 1st  ‘ 𝑠 ) )  ∪  { ( 2nd  ‘ 𝑠 ) } ) ) ) ) ) | 
						
							| 22 |  | inidm | ⊢ ( ( ∪  ( ( mVars ‘ 𝑇 )  “  ( ( 2nd  ‘ ( 1st  ‘ 𝑠 ) )  ∪  { ( 2nd  ‘ 𝑠 ) } ) )  ×  ∪  ( ( mVars ‘ 𝑇 )  “  ( ( 2nd  ‘ ( 1st  ‘ 𝑠 ) )  ∪  { ( 2nd  ‘ 𝑠 ) } ) ) )  ∩  ( ∪  ( ( mVars ‘ 𝑇 )  “  ( ( 2nd  ‘ ( 1st  ‘ 𝑠 ) )  ∪  { ( 2nd  ‘ 𝑠 ) } ) )  ×  ∪  ( ( mVars ‘ 𝑇 )  “  ( ( 2nd  ‘ ( 1st  ‘ 𝑠 ) )  ∪  { ( 2nd  ‘ 𝑠 ) } ) ) ) )  =  ( ∪  ( ( mVars ‘ 𝑇 )  “  ( ( 2nd  ‘ ( 1st  ‘ 𝑠 ) )  ∪  { ( 2nd  ‘ 𝑠 ) } ) )  ×  ∪  ( ( mVars ‘ 𝑇 )  “  ( ( 2nd  ‘ ( 1st  ‘ 𝑠 ) )  ∪  { ( 2nd  ‘ 𝑠 ) } ) ) ) | 
						
							| 23 | 22 | ineq2i | ⊢ ( ( 1st  ‘ ( 1st  ‘ 𝑠 ) )  ∩  ( ( ∪  ( ( mVars ‘ 𝑇 )  “  ( ( 2nd  ‘ ( 1st  ‘ 𝑠 ) )  ∪  { ( 2nd  ‘ 𝑠 ) } ) )  ×  ∪  ( ( mVars ‘ 𝑇 )  “  ( ( 2nd  ‘ ( 1st  ‘ 𝑠 ) )  ∪  { ( 2nd  ‘ 𝑠 ) } ) ) )  ∩  ( ∪  ( ( mVars ‘ 𝑇 )  “  ( ( 2nd  ‘ ( 1st  ‘ 𝑠 ) )  ∪  { ( 2nd  ‘ 𝑠 ) } ) )  ×  ∪  ( ( mVars ‘ 𝑇 )  “  ( ( 2nd  ‘ ( 1st  ‘ 𝑠 ) )  ∪  { ( 2nd  ‘ 𝑠 ) } ) ) ) ) )  =  ( ( 1st  ‘ ( 1st  ‘ 𝑠 ) )  ∩  ( ∪  ( ( mVars ‘ 𝑇 )  “  ( ( 2nd  ‘ ( 1st  ‘ 𝑠 ) )  ∪  { ( 2nd  ‘ 𝑠 ) } ) )  ×  ∪  ( ( mVars ‘ 𝑇 )  “  ( ( 2nd  ‘ ( 1st  ‘ 𝑠 ) )  ∪  { ( 2nd  ‘ 𝑠 ) } ) ) ) ) | 
						
							| 24 | 21 23 | eqtri | ⊢ ( ( ( 1st  ‘ ( 1st  ‘ 𝑠 ) )  ∩  ( ∪  ( ( mVars ‘ 𝑇 )  “  ( ( 2nd  ‘ ( 1st  ‘ 𝑠 ) )  ∪  { ( 2nd  ‘ 𝑠 ) } ) )  ×  ∪  ( ( mVars ‘ 𝑇 )  “  ( ( 2nd  ‘ ( 1st  ‘ 𝑠 ) )  ∪  { ( 2nd  ‘ 𝑠 ) } ) ) ) )  ∩  ( ∪  ( ( mVars ‘ 𝑇 )  “  ( ( 2nd  ‘ ( 1st  ‘ 𝑠 ) )  ∪  { ( 2nd  ‘ 𝑠 ) } ) )  ×  ∪  ( ( mVars ‘ 𝑇 )  “  ( ( 2nd  ‘ ( 1st  ‘ 𝑠 ) )  ∪  { ( 2nd  ‘ 𝑠 ) } ) ) ) )  =  ( ( 1st  ‘ ( 1st  ‘ 𝑠 ) )  ∩  ( ∪  ( ( mVars ‘ 𝑇 )  “  ( ( 2nd  ‘ ( 1st  ‘ 𝑠 ) )  ∪  { ( 2nd  ‘ 𝑠 ) } ) )  ×  ∪  ( ( mVars ‘ 𝑇 )  “  ( ( 2nd  ‘ ( 1st  ‘ 𝑠 ) )  ∪  { ( 2nd  ‘ 𝑠 ) } ) ) ) ) | 
						
							| 25 | 24 | a1i | ⊢ ( 𝑠  ∈  ( mPreSt ‘ 𝑇 )  →  ( ( ( 1st  ‘ ( 1st  ‘ 𝑠 ) )  ∩  ( ∪  ( ( mVars ‘ 𝑇 )  “  ( ( 2nd  ‘ ( 1st  ‘ 𝑠 ) )  ∪  { ( 2nd  ‘ 𝑠 ) } ) )  ×  ∪  ( ( mVars ‘ 𝑇 )  “  ( ( 2nd  ‘ ( 1st  ‘ 𝑠 ) )  ∪  { ( 2nd  ‘ 𝑠 ) } ) ) ) )  ∩  ( ∪  ( ( mVars ‘ 𝑇 )  “  ( ( 2nd  ‘ ( 1st  ‘ 𝑠 ) )  ∪  { ( 2nd  ‘ 𝑠 ) } ) )  ×  ∪  ( ( mVars ‘ 𝑇 )  “  ( ( 2nd  ‘ ( 1st  ‘ 𝑠 ) )  ∪  { ( 2nd  ‘ 𝑠 ) } ) ) ) )  =  ( ( 1st  ‘ ( 1st  ‘ 𝑠 ) )  ∩  ( ∪  ( ( mVars ‘ 𝑇 )  “  ( ( 2nd  ‘ ( 1st  ‘ 𝑠 ) )  ∪  { ( 2nd  ‘ 𝑠 ) } ) )  ×  ∪  ( ( mVars ‘ 𝑇 )  “  ( ( 2nd  ‘ ( 1st  ‘ 𝑠 ) )  ∪  { ( 2nd  ‘ 𝑠 ) } ) ) ) ) ) | 
						
							| 26 | 25 | oteq1d | ⊢ ( 𝑠  ∈  ( mPreSt ‘ 𝑇 )  →  〈 ( ( ( 1st  ‘ ( 1st  ‘ 𝑠 ) )  ∩  ( ∪  ( ( mVars ‘ 𝑇 )  “  ( ( 2nd  ‘ ( 1st  ‘ 𝑠 ) )  ∪  { ( 2nd  ‘ 𝑠 ) } ) )  ×  ∪  ( ( mVars ‘ 𝑇 )  “  ( ( 2nd  ‘ ( 1st  ‘ 𝑠 ) )  ∪  { ( 2nd  ‘ 𝑠 ) } ) ) ) )  ∩  ( ∪  ( ( mVars ‘ 𝑇 )  “  ( ( 2nd  ‘ ( 1st  ‘ 𝑠 ) )  ∪  { ( 2nd  ‘ 𝑠 ) } ) )  ×  ∪  ( ( mVars ‘ 𝑇 )  “  ( ( 2nd  ‘ ( 1st  ‘ 𝑠 ) )  ∪  { ( 2nd  ‘ 𝑠 ) } ) ) ) ) ,  ( 2nd  ‘ ( 1st  ‘ 𝑠 ) ) ,  ( 2nd  ‘ 𝑠 ) 〉  =  〈 ( ( 1st  ‘ ( 1st  ‘ 𝑠 ) )  ∩  ( ∪  ( ( mVars ‘ 𝑇 )  “  ( ( 2nd  ‘ ( 1st  ‘ 𝑠 ) )  ∪  { ( 2nd  ‘ 𝑠 ) } ) )  ×  ∪  ( ( mVars ‘ 𝑇 )  “  ( ( 2nd  ‘ ( 1st  ‘ 𝑠 ) )  ∪  { ( 2nd  ‘ 𝑠 ) } ) ) ) ) ,  ( 2nd  ‘ ( 1st  ‘ 𝑠 ) ) ,  ( 2nd  ‘ 𝑠 ) 〉 ) | 
						
							| 27 | 20 26 | eqtrd | ⊢ ( 𝑠  ∈  ( mPreSt ‘ 𝑇 )  →  ( 𝑅 ‘ 〈 ( ( 1st  ‘ ( 1st  ‘ 𝑠 ) )  ∩  ( ∪  ( ( mVars ‘ 𝑇 )  “  ( ( 2nd  ‘ ( 1st  ‘ 𝑠 ) )  ∪  { ( 2nd  ‘ 𝑠 ) } ) )  ×  ∪  ( ( mVars ‘ 𝑇 )  “  ( ( 2nd  ‘ ( 1st  ‘ 𝑠 ) )  ∪  { ( 2nd  ‘ 𝑠 ) } ) ) ) ) ,  ( 2nd  ‘ ( 1st  ‘ 𝑠 ) ) ,  ( 2nd  ‘ 𝑠 ) 〉 )  =  〈 ( ( 1st  ‘ ( 1st  ‘ 𝑠 ) )  ∩  ( ∪  ( ( mVars ‘ 𝑇 )  “  ( ( 2nd  ‘ ( 1st  ‘ 𝑠 ) )  ∪  { ( 2nd  ‘ 𝑠 ) } ) )  ×  ∪  ( ( mVars ‘ 𝑇 )  “  ( ( 2nd  ‘ ( 1st  ‘ 𝑠 ) )  ∪  { ( 2nd  ‘ 𝑠 ) } ) ) ) ) ,  ( 2nd  ‘ ( 1st  ‘ 𝑠 ) ) ,  ( 2nd  ‘ 𝑠 ) 〉 ) | 
						
							| 28 | 16 | fveq2d | ⊢ ( 𝑠  ∈  ( mPreSt ‘ 𝑇 )  →  ( 𝑅 ‘ ( 𝑅 ‘ 𝑠 ) )  =  ( 𝑅 ‘ 〈 ( ( 1st  ‘ ( 1st  ‘ 𝑠 ) )  ∩  ( ∪  ( ( mVars ‘ 𝑇 )  “  ( ( 2nd  ‘ ( 1st  ‘ 𝑠 ) )  ∪  { ( 2nd  ‘ 𝑠 ) } ) )  ×  ∪  ( ( mVars ‘ 𝑇 )  “  ( ( 2nd  ‘ ( 1st  ‘ 𝑠 ) )  ∪  { ( 2nd  ‘ 𝑠 ) } ) ) ) ) ,  ( 2nd  ‘ ( 1st  ‘ 𝑠 ) ) ,  ( 2nd  ‘ 𝑠 ) 〉 ) ) | 
						
							| 29 | 27 28 16 | 3eqtr4d | ⊢ ( 𝑠  ∈  ( mPreSt ‘ 𝑇 )  →  ( 𝑅 ‘ ( 𝑅 ‘ 𝑠 ) )  =  ( 𝑅 ‘ 𝑠 ) ) | 
						
							| 30 |  | fveq2 | ⊢ ( ( 𝑅 ‘ 𝑠 )  =  𝑋  →  ( 𝑅 ‘ ( 𝑅 ‘ 𝑠 ) )  =  ( 𝑅 ‘ 𝑋 ) ) | 
						
							| 31 |  | id | ⊢ ( ( 𝑅 ‘ 𝑠 )  =  𝑋  →  ( 𝑅 ‘ 𝑠 )  =  𝑋 ) | 
						
							| 32 | 30 31 | eqeq12d | ⊢ ( ( 𝑅 ‘ 𝑠 )  =  𝑋  →  ( ( 𝑅 ‘ ( 𝑅 ‘ 𝑠 ) )  =  ( 𝑅 ‘ 𝑠 )  ↔  ( 𝑅 ‘ 𝑋 )  =  𝑋 ) ) | 
						
							| 33 | 29 32 | syl5ibcom | ⊢ ( 𝑠  ∈  ( mPreSt ‘ 𝑇 )  →  ( ( 𝑅 ‘ 𝑠 )  =  𝑋  →  ( 𝑅 ‘ 𝑋 )  =  𝑋 ) ) | 
						
							| 34 | 33 | rexlimiv | ⊢ ( ∃ 𝑠  ∈  ( mPreSt ‘ 𝑇 ) ( 𝑅 ‘ 𝑠 )  =  𝑋  →  ( 𝑅 ‘ 𝑋 )  =  𝑋 ) | 
						
							| 35 | 7 34 | sylbi | ⊢ ( 𝑋  ∈  ran  𝑅  →  ( 𝑅 ‘ 𝑋 )  =  𝑋 ) | 
						
							| 36 | 1 2 | mstaval | ⊢ 𝑆  =  ran  𝑅 | 
						
							| 37 | 35 36 | eleq2s | ⊢ ( 𝑋  ∈  𝑆  →  ( 𝑅 ‘ 𝑋 )  =  𝑋 ) |