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authorJosh Chen2020-05-27 22:16:42 +0200
committerJosh Chen2020-05-27 22:16:42 +0200
commitf12983b1b53c71fc416155ac4b7e2b11ed8ca9ef (patch)
treeaa8370faefd779bbdf45676e77001c25a4d3f5cc /spartan/data/Maybe.thy
parented41980ed5cee12d7c5eea2e40627e5a390a83f8 (diff)
change variable name in elim rules and fix small mistake
Diffstat (limited to '')
-rw-r--r--spartan/data/Maybe.thy4
1 files changed, 4 insertions, 0 deletions
diff --git a/spartan/data/Maybe.thy b/spartan/data/Maybe.thy
index dc3ad04..98f5283 100644
--- a/spartan/data/Maybe.thy
+++ b/spartan/data/Maybe.thy
@@ -1,8 +1,12 @@
+chapter \<open>Maybe type\<close>
+
theory Maybe
imports More_Types
begin
+text \<open>Defined as a sum.\<close>
+
definition "Maybe A \<equiv> A \<or> \<top>"
definition "none A \<equiv> inr A \<top> tt"
definition "some A a \<equiv> inl A \<top> a"