| Step | Hyp | Ref | Expression | 
						
							| 1 |  | thlval.k | ⊢ 𝐾  =  ( toHL ‘ 𝑊 ) | 
						
							| 2 |  | thloc.c | ⊢  ⊥   =  ( ocv ‘ 𝑊 ) | 
						
							| 3 |  | fvex | ⊢ ( toInc ‘ ( ClSubSp ‘ 𝑊 ) )  ∈  V | 
						
							| 4 | 2 | fvexi | ⊢  ⊥   ∈  V | 
						
							| 5 |  | ocid | ⊢ oc  =  Slot  ( oc ‘ ndx ) | 
						
							| 6 | 5 | setsid | ⊢ ( ( ( toInc ‘ ( ClSubSp ‘ 𝑊 ) )  ∈  V  ∧   ⊥   ∈  V )  →   ⊥   =  ( oc ‘ ( ( toInc ‘ ( ClSubSp ‘ 𝑊 ) )  sSet  〈 ( oc ‘ ndx ) ,   ⊥  〉 ) ) ) | 
						
							| 7 | 3 4 6 | mp2an | ⊢  ⊥   =  ( oc ‘ ( ( toInc ‘ ( ClSubSp ‘ 𝑊 ) )  sSet  〈 ( oc ‘ ndx ) ,   ⊥  〉 ) ) | 
						
							| 8 |  | eqid | ⊢ ( ClSubSp ‘ 𝑊 )  =  ( ClSubSp ‘ 𝑊 ) | 
						
							| 9 |  | eqid | ⊢ ( toInc ‘ ( ClSubSp ‘ 𝑊 ) )  =  ( toInc ‘ ( ClSubSp ‘ 𝑊 ) ) | 
						
							| 10 | 1 8 9 2 | thlval | ⊢ ( 𝑊  ∈  V  →  𝐾  =  ( ( toInc ‘ ( ClSubSp ‘ 𝑊 ) )  sSet  〈 ( oc ‘ ndx ) ,   ⊥  〉 ) ) | 
						
							| 11 | 10 | fveq2d | ⊢ ( 𝑊  ∈  V  →  ( oc ‘ 𝐾 )  =  ( oc ‘ ( ( toInc ‘ ( ClSubSp ‘ 𝑊 ) )  sSet  〈 ( oc ‘ ndx ) ,   ⊥  〉 ) ) ) | 
						
							| 12 | 7 11 | eqtr4id | ⊢ ( 𝑊  ∈  V  →   ⊥   =  ( oc ‘ 𝐾 ) ) | 
						
							| 13 | 5 | str0 | ⊢ ∅  =  ( oc ‘ ∅ ) | 
						
							| 14 |  | fvprc | ⊢ ( ¬  𝑊  ∈  V  →  ( ocv ‘ 𝑊 )  =  ∅ ) | 
						
							| 15 | 2 14 | eqtrid | ⊢ ( ¬  𝑊  ∈  V  →   ⊥   =  ∅ ) | 
						
							| 16 |  | fvprc | ⊢ ( ¬  𝑊  ∈  V  →  ( toHL ‘ 𝑊 )  =  ∅ ) | 
						
							| 17 | 1 16 | eqtrid | ⊢ ( ¬  𝑊  ∈  V  →  𝐾  =  ∅ ) | 
						
							| 18 | 17 | fveq2d | ⊢ ( ¬  𝑊  ∈  V  →  ( oc ‘ 𝐾 )  =  ( oc ‘ ∅ ) ) | 
						
							| 19 | 13 15 18 | 3eqtr4a | ⊢ ( ¬  𝑊  ∈  V  →   ⊥   =  ( oc ‘ 𝐾 ) ) | 
						
							| 20 | 12 19 | pm2.61i | ⊢  ⊥   =  ( oc ‘ 𝐾 ) |