“…Plancherel
21 proved Plancherel's theorem in general form for the Fourier transform on
and confirmed that this transformation is unitary and this result is also still true for Hartley transforms. In Section 4, we give the Plancherel‐type theorem by using the techniques in Al‐Musallam and Tuan
4 and study the approximation in the norm of space
for the operator
constructed in formula (). Specifically, if suppose that the image function
and the original function
, then it can approximate to sequences of functions in the space
that converge normally in
to some arbitrary function which also belongs to
…”