From 6dde244c14410ede6d41e9a8607016e23c19e320 Mon Sep 17 00:00:00 2001
From: Greg Brown <greg.brown01@ed.ac.uk>
Date: Thu, 1 Feb 2024 15:23:47 +0000
Subject: Split monolithic file into modules.

Prove metatheory for generic initial algebras, instead of a clunky
concrete one.
---
 src/SOAS/Theory.idr | 58 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 58 insertions(+)
 create mode 100644 src/SOAS/Theory.idr

(limited to 'src/SOAS/Theory.idr')

diff --git a/src/SOAS/Theory.idr b/src/SOAS/Theory.idr
new file mode 100644
index 0000000..f36e7a1
--- /dev/null
+++ b/src/SOAS/Theory.idr
@@ -0,0 +1,58 @@
+module SOAS.Theory
+
+import SOAS.Algebra
+import SOAS.Context
+import SOAS.Family
+import SOAS.Strength
+import SOAS.Structure
+import SOAS.Var
+
+public export
+record (.Initial)
+         (signature : type.SortedFunctor)
+         (meta : type.SortedFamily)
+         (a : type.SortedFamily) where
+  constructor MkInitial
+  metalg : signature.MetaAlg meta a
+  bang :
+    (0 b : type.SortedFamily) ->
+    (metalg : signature.MetaAlg meta b) ->
+    a -|> b
+
+public export
+(.sem) :
+  signature .Initial meta a ->
+  (0 b : type.SortedFamily) -> (metalg : signature.MetaAlg meta b) =>
+  a -|> b
+init.sem b = init.bang b metalg
+
+%hint
+public export
+(.pointedCoalgStruct) :
+  (functoriality : signature.Map) =>
+  (str : Strength signature) =>
+  signature.Initial meta a -> type.PointedCoalgStruct a
+init.pointedCoalgStruct = MkPointedCoalgStruct
+  { ren = init.sem ([] a) @{traverse init.metalg.alg init.metalg.var init.metalg.mvar}
+  , var = init.metalg.var
+  }
+
+
+%hint
+public export
+(.monStruct) :
+  (functoriality : signature.Map) =>
+  (str : Strength signature) =>
+  signature.Initial meta a -> type.MonStruct a
+init.monStruct = MkSubstMonoidStruct
+  { var = init.metalg.var
+  , mult = init.sem (a ^ a) @{traverse init.metalg.alg id init.metalg.mvar}
+  }
+
+%hint
+public export
+(.monoidStruct) :
+  (functoriality : signature.Map) =>
+  (str : Strength signature) =>
+  signature.Initial meta a -> signature.MonoidStruct a
+init.monoidStruct = MkSignatureMonoid { mon = init.monStruct , alg = init.metalg.alg }
-- 
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