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Diffstat (limited to '')
| -rw-r--r-- | spartan/data/Maybe.thy | 4 |
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" |