Characterizing Corson and Valdivia compact spaces
  We give a new characterization of Valdivia compact spaces: A compact space is Valdivia if and only if it has a dense commutatively monotonically retractable subspace. This result solves Problem 5.12 from \cite{sal-rey}. Besides, we introduce the notion of full $c$-skeleton and prove that a compact space is Corson if and only if it has a full $c$-skeleton. 
F. Casarrubias-Segura, S. Garc\'ia-Ferreira, R. Rojas-Hern\'andez
math.GN