ABSTRACT
The transversality theorems of Thom and Mather have been used in a wide variety of situations to show that the family of maps satisfying certain families of conditions is dense (even, a dense Gδ -set) in the space of all maps. However although the original result of Thom showed that the set of maps was also open, this is not the case for later extensions of the result, and in particular theorems showing that a set of maps defined by multitransversality conditions is open are very few.
