Weak equivalences in the localized model structure on all simplicial sets
Determine whether, in the left Bousfield localized model structure L_{M^{-1}Z}SSets on all simplicial sets obtained by localizing at the set B_{M^{-1}Z} = { Sing(S^n) → Sing(S^n_{M^{-1}Z}) | n ≥ 2 }, the weak equivalences coincide with the M-local homotopy equivalences (i.e., those maps whose geometric realizations are M-local homotopy equivalences of spaces as in Definition 9.1).
References
Thus, the left Bousfield localization in Section 10 is only a partial extension of that in Section 7 to all simplicial sets: we produce model structures whose fibrant objects are the local simplicial sets, but we do not know whether the weak equivalences are the local homotopy equivalences.
— A modern perspective on rational homotopy theory
(2505.23322 - Chatzitheodoridis, 29 May 2025) in Section 9.1 (Localization of spaces)