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agda-spa/lean/Spa/Isomorphism.lean
2026-06-25 18:55:09 -05:00

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import Spa.Lattice
namespace Spa
def FiniteHeightLattice.transport {α β : Type*} [Lattice β]
[I : FiniteHeightLattice α] (f : α β) (g : β α)
(hf : Monotone f) (hg : Monotone g)
(hgf : Function.LeftInverse g f) (hfg : Function.LeftInverse f g) :
FiniteHeightLattice β where
toLattice := inferInstance
longestChain :=
I.longestChain.map f (hf.strictMono_of_injective hgf.injective)
chains_bounded := fun c =>
I.chains_bounded (c.map g (hg.strictMono_of_injective hfg.injective))
end Spa