cosection

co- +‎ section

cosection (plural cosections)

1. (mathematics) The left inverse of a morphism.
   • 2016, M. Kool, A. Gholampour, “Rank 2 wall-crossing and the Serre correspondence”, in arXiv‎:

     Provided ${\displaystyle {\mathcal {R}}}$ admits a cosection cutting out a 1-dimensional subscheme, we prove that the generating function of these Euler characteristics is equal to ${\displaystyle M(q)^{2e(X)}}$ times a polynomial of degree ${\displaystyle c_{3}({\mathcal {R}})}$.