Ask HN: What parts of software engineering can be quantified?
But I've also seen less-than-obvious quantifications and mathematical models. The second chapter of "Hello Startup!" represents a model of Agile vs Waterfall method in terms of total cost-under-curve for learning, complete with graphs.
I've also seen the process of debugging code be represented in Bayes Theorem, but that was only one problem in a textbook.
And of course anything by Knuth or Sedgewick tends to carry this flavour with their takes on data structures. But that's moving a bit far from software creation in the mobile-app and web-app sense.
What are examples of practical mathematical modelling and quantification in software-engineering?