Around a Hurewiczʼs formula

Some relevant questions around the Hurewiczʼs formula for the dimension-lowering mappings are under the discussion. In particular, we generalize the notion of a fully closed mapping introduced by V.V. Fedorchuk and find for such new mappings an evaluation formula for the dimension Ind0 (resp. Ind) of preimages via the dimension Ind0 (resp. Ind) of images.