Confused by zero moments

[Thomas Morley]

Hi,

consider the following:
musicI = {}
musicII = {}

Obviously ly:music-length returns #<Mom 0> for both:
#(pretty-print (ly:music-length musicI))
#(pretty-print (ly:music-length musicII))

Why the result of below is different:
#(pretty-print
  (ly:moment-div (ly:music-length musicI) (ly:music-length musicII)))
-> #<Mom 0>
#(pretty-print
   (ly:moment-div ZERO-MOMENT ZERO-MOMENT))
-> #<Mom nanGinfinity>

Thanks,
Harm