let V be RealLinearSpace; :: thesis: for p, q, y being Element of V
for a being Real st not are_Prop p,q & y = a * q & a <> 0 holds
not are_Prop p,y
let p, q, y be Element of V; :: thesis: for a being Real st not are_Prop p,q & y = a * q & a <> 0 holds
not are_Prop p,y
let a be Real; :: thesis: ( not are_Prop p,q & y = a * q & a <> 0 implies not are_Prop p,y )
assume that
A1: not are_Prop p,q and
A2: ( y = a * q & a <> 0 ) ; :: thesis: not are_Prop p,y
assume are_Prop p,y ; :: thesis: contradiction
then consider b being Real such that
A3: ( b <> 0 & p = b * y ) by ANPROJ_1:1;
( p = (b * a) * q & b * a <> 0 ) by A2, A3, RLVECT_1:def 7, XCMPLX_1:6;
hence contradiction by A1, ANPROJ_1:1; :: thesis: verum