  For two spatially anisotropic, SU(2)-invariant models of frustrated magnets
in arbitrary space dimension we present a non-perturbative proof of the
existence of neutral spin-1/2 excitations (spinons). In one model the
frustration is static and based on fine tuning of the coupling constants,
whereas in the other it is dynamic and does not require adjusting of the model
parameters. For both models we derive a low-energy effective action which does
not contain any constraints. Though our models admit the standard gauge theory
treatment, we follow an alternative approach based on Abelian and non-Abelian
bosonization. We prove the existence of propagating spin-1/2 excitations
(spinons) and consider in detail certain exactly solvable limits. A qualitative
discussion of the most general case is also presented.
