Stopping a peat-more fire

The problem is considered of stopping a peat-moor fire by digging a trench around it with a bulldozer and, in particular, the question of how large the digging speed must be in order to contain a fire of given extension and spreading speed. The treatment of the problem is intended to serve educational purposes, and show the use, on an elementary level, of dimensional analysis, geometry of curves and differential equations

On the existence of entire functions mapping countable dense sets onto each other

No abstract

A comment on unions of rings

No abstract