  The Land\'e or g-factors of charge carriers in solid state systems provide
invaluable information about response of quantum states to external magnetic
fields and are key ingredients in description of spin-dependent phenomena in
nanostructures. We report on the comprehensive theoretical analysis of electron
and hole g-factors in lead chalcogenide nanocrystals. By combining symmetry
analysis, atomistic calculations, and extended k.p theory, we relate calculated
linear-in-magnetic field energy splittings of confined electron states in
nanocrystals to the intravalley g-factors of the multi-valley bulk materials,
renormalized due to the quantum confinement. We demonstrate that this
renormalization is correctly reproduced by analytical expressions derived in
the framework of the extended k.p model.
