Obstruction theory in algebraic topology, Extension and compression of mappings in algebraic topology, Topology of vector bundles and fiber bundles, point defect, Homotopy groups of special types, defect set, Sectioning fiber spaces and bundles in algebraic topology, n- dimensional vector bundle, Article, defect class, regularly defect section, 510.mathematics, defect plane bundle, Characteristic classes and numbers in differential topology, boundary value problem, Generalities, axiomatics, foundations of continuum mechanics of solids, Euler characteristic, branched line bundle, branched double covering, Low-dimensional topology of special (e.g., branched) coverings