Functional decomposition is focused on that methods which are discrete such as the need for the Jackson Structured Programming for the manipulation of data. So, It is not the concrete step that is implemented for some detailed which is remain unspecified.
That's why the following statement is not correct according to the functional decomposition.
Concrete steps are those steps for which full explanation details of implementation is mentioned while abstract steps are those for which some details are not mentioned or specified.
functional decomposition is referred to as the technique to developed software. In functional decomposition, in which error is divided into smaller form and solution to each smaller error then combine to give the solution to the whole error.
