Generalized Weierstrass integrability for the complex differential equations dy/dx = a(x)y⁴+b(x)y³+c(x)y²+d(x) y+e(x)

We characterize the differential equations of the form dy/dx=a(x)y 4+b(x)y3+c(x)y2+d(x)y+e(x), where a,b,c,d,e are meromorphic functions in the variable x, that admits either a generalized Weierstrass first integral or a generalized Weierstrass inverse integrating factor. © 2013 Elsevier Ltd. All rights reserved.