My guess is that it was Prolog Development Center (PDC) [1] the company behind Turbo Prolog and Visual Prolog [2]. They built a nice business providing scheduli

My guess is that it was Prolog Development Center (PDC) [1] the company behind Turbo Prolog and Visual Prolog [2]. They built a nice business providing scheduling and planning software to airlines. They are still around if you want to get in touch. [1] https://www.pdc.com/ https://www.pdc.com/ [2] https://en.m.wikipedia.org/wiki/Visual_Prolog https://en.m.wikipedia.org/wiki/Visual_Prolog