What is the correct spelling of the word "null-space"?
Merriam-Webster puts it in a hyphenated form "null-space", (link).
Firefox's built-in spellchecker knows only "null space" and "null-space".
I've seen all three spellings in the existing scientific literature.
What would be the correct spelling according to grammar? Is there any difference if we are talking about AmE or BrE? Or should I just pick one spelling and use it across the whole article?