So I had to compromise with  operational research work, which had the intellectual challenge  that interested me and the commercial value  that was valued by the clients: things like scheduling freight trains, time-tabling buses, stock control, lots and lots of stock control.
Então, tive de desenvolver um trabalho de pesquisa operacional, o que tinha o desafio intelectual que me interessava e o valor comercial valorizado pelos clientes: coisas como organizar horários de trens de carga e de ônibus; controlar estoques, muito controle de estoque.