@misc{10481/49801, year = {2016}, month = {6}, url = {http://hdl.handle.net/10481/49801}, abstract = {Let N be the set of nonnegative integers. A problem about how to transport profitably an organized group of persons leads us to study the set T formed by the integers n such that the system of inequalities, with nonnegative integer coefficients, a_1x_1+⋯+a_px_p