G. Gallavotti, F. Guerra, S. Miracle-Sol\'e A comment to the talk by E. Seiler

In {\it Mathematical problems in theoretical Physics}, ed. G. Dell'Antonio, S.Doplicher, G. Jona--Lasinio, Lecture notes in Physics, {\bf 80}, 436--438, 1978


A comment providing a proof that the $Z^2$ gauge theory had a phase transition area-perimeter for the Wilson's loop expectation