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Definition of a Heyting algebra together with the adjunction + the (- x A) functor for cartesian categories

https://github.com/JetBrains/arend-lib/blob/d37974021d69917ef04f034c954a801e0de64223/src/Logic/Classical.ard#L26 lmfao

strange exception about dependencies in SubGroupPreorder

in src/Category.ard instead of | \fixl 8 o \alias \infixl 8 ∘ {X Y Z : Ob} : Hom Y Z -> Hom X Y -> Hom X Z make...

This is an interesting demonstration of higher inductive types.

There are several goals left in [Arith.Real](https://github.com/JetBrains/arend-lib/blob/b05bc6a39e24c4230e308f5c88f7b93023c21246/src/Arith/Real.ard): - [ ] The locatedness property for the product of two reals. - [ ] The locatedness property for the inverse of a...

help wanted

Meta `equation` finds the first appropriate instance, but it might not be the best. For example, it could use an instance of the Ring class instead of CRing if the...

meta

This is [Topology.Locale/wregular_wHausdorff](https://github.com/JetBrains/arend-lib/blob/4ea97da483c5bb2e6a22c8d09c03becf17756c7e/src/Topology/Locale.ard#L1364). A proof of this proposition can be found in Fibrewise separation axioms for locales, Peter T. Johnstone, 1990, Corollary 3.4. This proposition requires a lot of background...

help wanted

This is [Topology.Locale/open-comp](https://github.com/JetBrains/arend-lib/blob/4ea97da483c5bb2e6a22c8d09c03becf17756c7e/src/Topology/Locale.ard#L1194). A proof of this proposition can be found in Handbook of Categorical Algebra: Volume 3, Francis Borceux, 1994 (Chapter 1), Corollary 1.6.3.

help wanted