Now that the interfaces of the tt(Math) module and its partitions have been
defined (cf. figure ref(MathPart)) the tt(Math) module's members can be 
defined. The constructor of tt(class Add) in the tt(Math:Add) partition
needs a reference to a tt(Utility) object which it receives from tt(Math)
constructor:
    verbinsert(-as4 examples/partition/math/math1.cc)

Since tt(class Utility's count) member is public, it can be called by the
tt(Math::count) member:
    verbinsert(-as4 examples/partition/math/count.cc)

and finally, tt(Math's add) member calls tt(Add's sum) member, defined in the
tt(Math:Add) partition to obtain the sum of two positive integral values:
    verbinsert(-as4 examples/partition/math/add.cc)

