  It is commonly believed that in quantum Monte Carlo approaches to fermionic
many- body problems, the infamous sign problem generically implies
prohibitively large computational times for obtaining thermodynamic-limit
quantities. We point out that for convergent Feynman diagrammatic series
evaluated with the Monte Carlo algorithm of [Rossi, arXiv:1612.05184], the
computational time increases only polynomially with the inverse error on
thermodynamic-limit quantities.
