Constructive problem-solving is when one takes problems and dilemmas and composes them into solutions. A simple example is when two lonely, longing people meet and marry. Another, more prosaic, is when a producer converts wastes into useful by-products. Another, more general, is whenever demand meets supply.
An address by Mason Gaffney at a meeting of the Land Policy Council, London, The Grosvenor Hotel, May 17, 1998.