let r be Real; CAYLDICK:def 7 for a being Element of (Cayley-Dickson N) holds r * (a *') = (r * a) *'
let a be Element of (Cayley-Dickson N); r * (a *') = (r * a) *'
consider a1, a2 being Element of N such that
A1:
a = <%a1,a2%>
by Th12;
A2:
r * (- a2) = - (r * a2)
by RLVECT_1:25;
r * a = <%(r * a1),(r * a2)%>
by A1, Def9;
then A3:
(r * a) *' = <%((r * a1) *'),(- (r * a2))%>
by Def9;
A4:
r * (a1 *') = (r * a1) *'
by Def7;
a *' = <%(a1 *'),(- a2)%>
by A1, Def9;
hence
(r * a) *' = r * (a *')
by A2, A3, A4, Def9; verum