I stumbled over the term "Hesse-Matrix". A matrix is a mathematical object and a Hesse-Matrix is a particular matrix named after mathematician Ludwig Otto Hesse.
My first question is whether this requires the spelling "Hesse-Matrix" or whether "Hessematrix" and "Hesse Matrix" would also be admissible?
Furthermore, I noticed that some people (especially in spoken German) tend to use this term in the following sense "in der Hess(e)schen-Matrix stehen nur Nullen." instead of "in der Hesse-Matrix stehen nur Nullen."
So I am not sure about the particular spelling, since this refers especially to spoken German, but people often tend to put a 'schen' after the name. Is there any meaningful reason why one would do that?