G8 
which is capable of but one other variety, namely, 
A - B not-C or not-BC. 
Each of these propositions can be expressed in six apparently 
different modes, which on examination are found to have 
exactly the same logical meaning. 
A complete solution of the problem of three terms having 
been obtained, it is pointed out that the corresponding 
problem for four terms is almost impracticable, since it 
would involve the detailed examination of 65,536 different 
selections of combinations. The problem of five terms may 
be called impossible as regards complete solution, since it 
involves no less than 4,294,967,296 cases. Similarly, six 
terms admit of more than eighteen trillions of cases. Thus 
it is quite impossible that the complete solution of the 
inverse logical problem should ever be carried more than 
one step further than it has been done in this paper. 
