### Abstract

Approximate model counting is the task of approximating the number of solutions
to an input formula. This entry formalizes $\mathsf{ApproxMC}$, an algorithm
due to Chakraborty et al. with a
probably approximately correct (PAC) guarantee, i.e., $\mathsf{ApproxMC}$
returns a multiplicative $(1+\varepsilon)$-factor approximation of the model
count with probability at least $1 - \delta$, where $\varepsilon > 0$ and $0 <
\delta \leq 1$. The algorithmic specification is further refined to a verified
certificate checker that can be used to validate the results of untrusted
$\mathsf{ApproxMC}$ implementations (assuming access to trusted randomness).