Functional Forms In the below pages we introduce the forms and integrals of various popular IMFs. It is our hope this can serve as something more than a reference, where we cover some of the logic required for the derivations. Power Law (Salpeter 1955) Broken Power Law (Kroupa 2001) Chabrier (2003) L3 (Maschberger 2013) Lognormal Generalised Gamma (Wise+ 2012)