See e.g.:
Vladimir Arnold: Collected Works. Springer
Khovanskii, A.: Topological Galois Theory - Solvability and Unsolvability of Equations in Finite Terms. Springer 2014
Khovanskii, A.: One dimensional topological Galois theory. 2019
Askold Khovanskii - Publications
Vladimir Arnold: Collected Works. Springer
Khovanskii, A.: One dimensional topological Galois theory. 2019
Askold Khovanskii - Publications
For the topological proofs without connection to representability in meromorphic functions, see e.g.: