Erratum for ---- Equivariant semidefinite lifts and sum-of-squares hierarchies Hamza Fawzi, James Saunderson, Pablo A. Parrilo SIAM Journal on Optimization, vol.25, no.4, pp.2212--2243, 2015 ---- - In Theorem 5.1 page 2235: floor(n/2) should be replaced by ceil(n/2)-1. This has some (very minor) consequences on some other parts of the manuscript, namely in the paragraph ``Exponential lower bound'' page 2237: - Page 2237: ``Laurent's floor(n/2) lower bound'' -> ``Laurent's ceil(n/2) lower bound'' - Page 2237, in the proof of Theorem 1.8 one should take k=ceil(m/2) and the final lower bound is (n choose floor(n/4)) instead of (n choose ceil(n/4))