Step
*
of Lemma
strong-subtype_functionality
∀[A1,B1,A2,B2:Type]. (A1 ≡ A2
⇒ B1 ≡ B2
⇒ strong-subtype(A1;B1)
⇒ strong-subtype(A2;B2))
BY
{ (Unfold `strong-subtype` 0 THEN Auto) }
1
1. A1 : Type
2. B1 : Type
3. A2 : Type
4. B2 : Type
5. A1 ≡ A2@i
6. B1 ≡ B2@i
7. (A1 ⊆r B1) c∧ ({b:B1| ∃a:A1. (b = a ∈ B1)} ⊆r A1)@i
8. A2 ⊆r B2
⊢ {b:B2| ∃a:A2. (b = a ∈ B2)} ⊆r A2
Latex:
Latex:
\mforall{}[A1,B1,A2,B2:Type]. (A1 \mequiv{} A2 {}\mRightarrow{} B1 \mequiv{} B2 {}\mRightarrow{} strong-subtype(A1;B1) {}\mRightarrow{} strong-subtype(A2;B2))
By
Latex:
(Unfold `strong-subtype` 0 THEN Auto)
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