57M05 Fundamental group, presentations, free differential calculus
57M07 Topological methods in group theory
57M10 Covering spaces
57M12 Special coverings, e.g. branched
57M15 Relations with graph theory [See also 05Cxx]
57M20 Two-dimensional complexes
57M25 Knots and links in $S^3$ {For higher dimensions, see 57Q45}
57M27 Invariants of knots and 3-manifolds
57M30 Wild knots and surfaces, etc., wild embeddings
57M35 Dehn's lemma, sphere theorem, loop theorem, asphericity
57M40 Characterizations of $E^3$ and $S^3$ (Poincaré conjecture) [See also 57N12]
57M50 Geometric structures on low-dimensional manifolds
57M60 Group actions in low dimensions
57M99 None of the above, but in this section