I have no doubt writing fiction isn't easy. I'm just saying that in general, a math book like I mentioned takes more time and expertise to write than fiction. Not in the first place because it requires that you have at least the level of expertise of a graduate student (which is 5 years of study). I'm not sure what Ulyssess being intensively studied has to with it. The only thing which makes a math book easier to write is that it's more accepted to distribute the work between different writers.
Some caveats apply: Many professors have teached a course repeatedly, at which they have such a level of mastery of the subject that they can just bang out the theorems and proofs (I've had one professor who wrote the 300 pages of lecture notes during the course). When the book actually contains new information, it takes much longer.
Some caveats apply: Many professors have teached a course repeatedly, at which they have such a level of mastery of the subject that they can just bang out the theorems and proofs (I've had one professor who wrote the 300 pages of lecture notes during the course). When the book actually contains new information, it takes much longer.