Infinite log-concavity for polynomial Pólya frequency sequences

Petter Brändén, Matthew Chasse

McNamara and Sagan conjectured that if $a_0,a_1,a_2,\dots$ is a Pólya frequency (PF) sequence, then so is $a_0^2,a_1^2-a_0{a}_2,a_2^2-a_1{a}_3,\dots$. We prove this conjecture…