let X be RealNormSpace; :: thesis: for f, g, h being Element of BoundedLinearOperators X,X holds f * (g + h) = (f * g) + (f * h)
let f, g, h be Element of BoundedLinearOperators X,X; :: thesis: f * (g + h) = (f * g) + (f * h)
set BLOP = R_NormSpace_of_BoundedLinearOperators X,X;
set ADD = Add_ (BoundedLinearOperators X,X),(R_VectorSpace_of_LinearOperators X,X);
set mf = modetrans f,X,X;
set mg = modetrans g,X,X;
set mh = modetrans h,X,X;
set mgh = modetrans (g + h),X,X;
(Add_ (BoundedLinearOperators X,X),(R_VectorSpace_of_LinearOperators X,X)) . ((modetrans f,X,X) * (modetrans g,X,X)),((modetrans f,X,X) * (modetrans h,X,X)) = (modetrans f,X,X) * (modetrans (g + h),X,X)
proof
reconsider gg = g as VECTOR of (R_NormSpace_of_BoundedLinearOperators X,X) ;
reconsider hh = h as VECTOR of (R_NormSpace_of_BoundedLinearOperators X,X) ;
A1: gg = modetrans g,X,X by LOPBAN_1:def 12;
A2: hh = modetrans h,X,X by LOPBAN_1:def 12;
reconsider k = (modetrans f,X,X) * (modetrans (g + h),X,X) as VECTOR of (R_NormSpace_of_BoundedLinearOperators X,X) by LOPBAN_1:def 10;
reconsider fg = (modetrans f,X,X) * (modetrans g,X,X) as VECTOR of (R_NormSpace_of_BoundedLinearOperators X,X) by LOPBAN_1:def 10;
reconsider fh = (modetrans f,X,X) * (modetrans h,X,X) as VECTOR of (R_NormSpace_of_BoundedLinearOperators X,X) by LOPBAN_1:def 10;
for x being VECTOR of X holds ((modetrans f,X,X) * (modetrans (g + h),X,X)) . x = (((modetrans f,X,X) * (modetrans g,X,X)) . x) + (((modetrans f,X,X) * (modetrans h,X,X)) . x)
proof
let x be VECTOR of X; :: thesis: ((modetrans f,X,X) * (modetrans (g + h),X,X)) . x = (((modetrans f,X,X) * (modetrans g,X,X)) . x) + (((modetrans f,X,X) * (modetrans h,X,X)) . x)
A3: g + h = gg + hh ;
modetrans (g + h),X,X = g + h by LOPBAN_1:def 12;
then A4: (modetrans (g + h),X,X) . x = ((modetrans g,X,X) . x) + ((modetrans h,X,X) . x) by A1, A2, A3, LOPBAN_1:41;
thus ((modetrans f,X,X) * (modetrans (g + h),X,X)) . x = (modetrans f,X,X) . ((modetrans (g + h),X,X) . x) by Th4
.= ((modetrans f,X,X) . ((modetrans g,X,X) . x)) + ((modetrans f,X,X) . ((modetrans h,X,X) . x)) by A4, LOPBAN_1:def 5
.= (((modetrans f,X,X) * (modetrans g,X,X)) . x) + ((modetrans f,X,X) . ((modetrans h,X,X) . x)) by Th4
.= (((modetrans f,X,X) * (modetrans g,X,X)) . x) + (((modetrans f,X,X) * (modetrans h,X,X)) . x) by Th4 ; :: thesis: verum
end;
then k = fg + fh by LOPBAN_1:41;
hence (Add_ (BoundedLinearOperators X,X),(R_VectorSpace_of_LinearOperators X,X)) . ((modetrans f,X,X) * (modetrans g,X,X)),((modetrans f,X,X) * (modetrans h,X,X)) = (modetrans f,X,X) * (modetrans (g + h),X,X) ; :: thesis: verum
end;
hence f * (g + h) = (f * g) + (f * h) ; :: thesis: verum