def geometric_conj_af(a, f):
 (a, f) = map(sympify, (a, f))
 return (- geometric_conj_ab(a, (- f)))

def geometric_conj_af ( a , f ) : ( a , f ) = map ( sympify , ( a , f ) ) return ( - geometric_conj_ab ( a , ( - f ) ) )
conjugation relation for geometrical beams under paraxial conditions .