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+(*  Title:  HoTT/Empty.thy
+    Author: Josh Chen
+
+Empty type
+*)
+
+theory Empty
+  imports HoTT_Base
+begin
+
+
+section \<open>Constants and type rules\<close>
+
+section \<open>Empty type\<close>
+
+axiomatization
+  Empty :: Term  ("\<zero>") and
+  indEmpty :: "Term \<Rightarrow> Term"  ("(1ind\<^sub>\<zero>)")
+where
+  Empty_form: "\<zero> : U(O)"
+and
+  Empty_elim: "\<lbrakk>C: \<zero> \<longrightarrow> U(i); z: \<zero>\<rbrakk> \<Longrightarrow> ind\<^sub>\<zero>(z): C(z)"
+
+
+text "Rule attribute declarations:"
+
+lemmas Empty_routine [intro] = Empty_form Empty_elim
+
+
+end