“…The 4-dimensional gauge theoretic origin of 2-dimensional integrable field theories, as proposed by Costello and Yamazaki in [CY], has been extensively studied over the past couple of years, see for instance [DLMV3,Sc1,FSY1,FSY2,CS,T,THC,BSV,BS,LV,CSV,FSY3,ABW,FSY4,D,St,Sc2,L2,FSY5].…”