(* Author: Ning Zhang and Christian Urban
Example theory involving Unicode characters (UTF-8 encoding) -- both
formal and informal ones.
*)
section \<open>A Chinese theory\<close>
theory Chinese imports Main begin
text\<open>数学家能把咖啡变成理论,如今中国的数学家也可
以在伊莎贝拉的帮助下把茶变成理论.
伊莎贝拉-世界数学家的新宠,现今能识别中文,成为
中国数学家理论推导的得力助手.
\<close>
datatype shuzi =
One ("一")
| Two ("二")
| Three ("三")
| Four ("四")
| Five ("五")
| Six ("六")
| Seven ("七")
| Eight ("八")
| Nine ("九")
| Ten ("十")
primrec translate :: "shuzi \<Rightarrow> nat" ("|_|" [100] 100) where
"|一| = 1"
|"|二| = 2"
|"|三| = 3"
|"|四| = 4"
|"|五| = 5"
|"|六| = 6"
|"|七| = 7"
|"|八| = 8"
|"|九| = 9"
|"|十| = 10"
thm translate.simps
lemma "|四| + |六| = |十|"
by simp
end