“…One of the main difficulties we face when dealing with regularity issues for nonlocal equations is the lack of a corresponding isoperimetric inequality for W s,p functions. Indeed, since such functions can have jumps, a generic isoperimetric inequality seems out of reach at this time (see [14,1] ) One way around this issue is to note that since we are working with solutions of an equation, which we expect to be continuous and hence have no jumps, we could try and cook up an isoperimetric inequality for solutions. Such a strategy turns out to be feasible due to the presence of the "good term" or the isoperimetric term in the Caccioppoli inequality.…”