Acknowledgement of priority - A fractional Helly theorem for boxes.

In our recent paper [1] we prove a fractional Helly type theorem for boxes in Rd. This short note is to acknowledgepriority: in 1980 Meir Katchalski [4] proved exactly the same result and in 1988 Jurgen Eckhoff [2] proved the same resultin much more generality. In fact, Eckhoff established an upper bound theorem for the f -vectors of finite families of boxesin Rd from which his result is derived. Besides apologies for our ignorance we would like to mention that Eckhoff extendedhis results further in a more recent paper [3].