Kock A. and G.E. Reyes (2001). Some differential equations in SDG. arXiv:math.CT/0104164 17 April 2001

This paper has been superseded. Its contents have been improved and re-written by the authors as three separate papers: “Some calculus with extensive quantities: wave equation”, “Categorical distribution theory; heat equation” and “Ordinary differential equations and their exponentials”. These papers may be unloaded here. I enclose it because it gives a bird’s view on our project.