(* -*- isar -*-
Example proof document for Isabelle/Isar Proof General.
$Id$
The first line forces Isabelle/Isar Proof General, otherwise
you may get the theory mode of ordinary Isabelle Proof General
*)
theory Example = Main:
theorem and_comms: "A & B --> B & A"
proof
assume "A & B"
thus "B & A"
proof
assume A B
show ?thesis
..
qed
qed
end