_What is a Lefschetz pencil?_ by Robert Gompf
_What is a Lefschetz pencil?_ by Robert Gompf -- source link
#pencil#algebraic geometry#dehn twist#max dehn#kirby calculus#robion kirby#solomon lefschetz#manifolds#surgery#topology#mathematics#maths#blowing up#blowup#projective geometry#singularity#singularities#fibrations#genus#surfaces#excision#4manifolds#bundles#monodromy#cylinder#torus