Are multiple colons in technical papers allowed? [closed]
Solution 1:
The punctuation looks awkward but it is perfectly understandable. You could just leave out the colons.
Alternatively you could change your sentence to
There is a set of parameters defined by them; x is the number of boys, y is the number of girls, and z is the overall population size.
A mathematical article might say
Let x be the number of boys, let y be the number of girls, and let z be the overall population size.