let M be MidSp; :: thesis: for a being Element of M
for u being Vector of M ex b being Element of M st u = vect (a,b)

let a be Element of M; :: thesis: for u being Vector of M ex b being Element of M st u = vect (a,b)
let u be Vector of M; :: thesis: ex b being Element of M st u = vect (a,b)
consider b being Element of M such that
A1: u = [a,b] ~ by Th34;
u = vect (a,b) by A1;
hence ex b being Element of M st u = vect (a,b) ; :: thesis: verum