I remember way back when (like about 50 or so years ago) about a crew of maths guys flying a ship through something like tensor space - an actualisation of maths. I cannot for the life of me (or google) remember what it was called or who it was by. Might be on that web page, but too difficult to navigate for me!

Neverness by David Zindell? Not quite 50 years though.

I know what you mean, but that's not it - this was a short story.