Hello Lukas,
I had the same question before but it was not concluded. As a
workaround, I'm declaring the two rewrites and it works for any number
of assumptions.
"⋀Q. (True ⟹ PROP Q) ≡ Q" and "⋀Q. (True ⟹ Q) ≡ Trueprop Q"
Best regards,
Akihisa
On 2021/02/05 22:15, Lukas Stevens wrote:

Hello,

`suppose I have a locale foo_on that assumes that some predicate P
``holds on a carrier set A. Often, one wants to specialise this to a
``locale foo where A is the UNIV. The problem is that theorems in foo_on
``often have assumptions of the form "X ⊆ A" which are "X ⊆ UNIV" in the
``context of foo. Those assumptions are trivial so I want to get rid of
``them using rewrites but this doesn't seem to work as the example below
``shows:
`
axiomatization P :: "'a ⇒ bool"
locale foo =
fixes A :: "'a set"
begin
lemma bar: "X ⊆ A ⟹ P X"
sorry
end
locale bar
begin

`(* (True ==> Q) ≡ Trueprop Q works for the theorem bar but not for
``theorems with multiple assumptions. *)
``sublocale foo UNIV rewrites "Y ⊆ UNIV ≡ True" and "(True ⟹ PROP Q) ≡
``PROP Q"
` by auto
end
What is going wrong here?
Cheers,
Lukas