We study various representations of the infrared effective theory of SU(2)
gluodynamics starting from the monopole action derived recently.
We determine the coupling constants in the abelian-Higgs model directly from
lattice QCD and evaluate the type of the QCD vacuum. The string action is
derived using the BKT transformation on the lattice. At the classical level
this action reproduces the physical string tension with a good accuracy.Comment: 3 pages, LaTeX, 2 figures; talk presented at LATTICE9
