Nodes of a general plane projection of a projective curve

Abstract

Let X⊂ P n , n⩾6, be an irreducible non-degenerate curve and f:X→ P 2 its general plane projection. Set Z≔ Sing(f(X))⧹f ( Sing(X)) and z≔card( Z). If n⩽7 assume z⩾25. Here we prove that the monodromy group of the generic apparent singular set Z is either the alternating group on z elements or the full symmetric group on z elements.