Re: Problem space and solution space

["Alexandre E. Kopilovitch" <aek@vib.usr.pu.ru>]

maa@liacc.up.pt (M?rio Amado Alves) writes:
><<parts of "solution space" may be viewed as a "problem space" of
>software development process>> (Alexander)
>
>A typical situation occurs in the chain
>  1 requirements specification
>  2 design
>  3 program
>where 1 is a problem to the designer, 2 is a solution to 1, 2 is a
>problem to the programmer, and 3 is a solution to 2 (and transitively
>to 1).

No, that is only the middle part of the actual chain, which is more like this:

1 real-world problem              -- here we are in problem space

2 requirements specification      -- here we are still in problem space

3 design                          -- here we construct a mapping from some
                                  -- decomposition of the problem space into
                                  -- some decomposition of solution space

4 program                         -- here we are in solution space

5 production run and maintenance. -- is there an easy-to-follow bidirectional
                                  -- correspondence between the problem space
                                  -- and the solution space ?

Most important thing here is that we should consider solution spaces with
no less attention then problem spaces. This means that we should indeed treat
them as spaces of some sort, and try to apply to them systematically the same
approaches and notions that we routinely associate with various kinds of spaces.
  With that understanding the whole chain looks (well, I admit, quite vaguely)
as a process of construction of some sort of correspondence between the problem
space and the solution space. The task of controlling that process has its own
problem space, and this one is that I tried to tell about in my previous posting
under this subject line.
  Finally, I'd like to mention, that this view was not justified until relatively
recently (perhaps, not earlier then 1980 or so), because there was no substantial
space of solutions for general use; the available ready-to-use solutions were
mostly isolated.


Alexander Kopilovitch                      aek@vib.usr.pu.ru
Saint-Petersburg
Russia