Disclaimers: I am neither a musician, nor I want to discredit Mazzola's work. Corollary of the first point: please use a plain style, without technical terms in the area of Music Theory. Corollary of the second: don't take my disbelief in Mazzola's work as an offense. ;)
So, the question is: what is Mazzola's "Topos of music" about? Is the considerable required amount of advanced Mathematics a necessary tool to achieve the goals of the book? Can a discrete knowledge of those mathematical prerequisite shed some light to the mathematical approach to music theory? Does somebody out there managed to apply Mazzola's ideas (if there are some, sensible to be applied) to a "concrete" situation?