“…However, there is also a recent stream of work on exponential tractability, and this is what we are going to study here. For results on exponential tractability for general linear problems (without necessarily assuming tensor product structure), we refer the reader to the recent paper [12], for exponential tractability for linear problems on un-weighted tensor product spaces, we refer the reader to [4,21,22]. Further results on exponential tractability can, e.g., be found in the papers [1,2,6,7,8,10,11,13,14,15,16,23,27,28,31,33].…”