let L be Z_Lattice; for v being Vector of L holds
( <;v,(0. L);> = 0 & <;(0. L),v;> = 0 )
let v be Vector of L; ( <;v,(0. L);> = 0 & <;(0. L),v;> = 0 )
thus <;v,(0. L);> =
<;v,(v - v);>
by RLVECT_1:15
.=
<;v,v;> - <;v,v;>
by ThSc5
.=
0
; <;(0. L),v;> = 0
thus <;(0. L),v;> =
<;(v - v),v;>
by RLVECT_1:15
.=
<;v,v;> - <;v,v;>
by ThSc5
.=
0
; verum