Epimorphisms of partial geometries onto generalized quadrangles
It is well known that a homomorphism from a finite projective plane onto another must be an isomorphism unless it is trivial. (There is only one image point.) A generalized quadrangle is a kind of ``partial geometry''. The authors prove that there is no proper epimorphism from a partial geometry onto a generalized quadrangle.
scientific article; zbMATH DE number 4111446