  We summarize and extend evidence that the deconfinement phase transition in
Yang-Mills theories can be viewed as change of effective non-perturbative
degrees of freedom and of symmetries of their interactions. In short, the
strings in four dimensions (4d) at temperatures below the critical temperature
Tc are replaced by particles, or field theories in 3d at T>Tc. The picture
emerges within various approaches based, in particular, on dual models, lattice
data and field theoretic models. We concentrate mostly on the lattice data, or
on the language of quantum geometry.

High Energy Physics - Phenomenology;High Energy Physics - Lattice;High Energy Physics - Theory