In Brown's book "Boolean reasoning: the logic of Boolean equations.", Chapter 5.7 Selection deduction, he does an example using 'a modification of one given by Ledley', which uses Blake Canonical form and clausal forms to answer questions pertaining to a biochemical experiment. His example differs from the original by adding another experimental outcome and changing the questions being asked. I was able to follow his reasoning and reproduce the equations and solution shown in the book.
However, when I looked at the original referenced Ledley paper, a government document from 1954, I seemed lost on how the conclusions on the second page were made.
In Brown's modified version clausal forms were deduced, such as XY->Z "Thus the following is known, independent of any knowledge of enzyme content: if reactions X and Z occur together, then reaction Y occurs also."
Ledley's original version seems to find solutions for each variable, and for X two different solutions. How? I seem to be at a lost to how his results were even started.
This is just self-study and trying to understand Boolean theory more.
Reference to document and relevant pages attached.
Ledley, R.S., "A digitalization, systematization, and formulation of the theory and methods of the propositional calculus," NBS Report 3363, National Bureau of Standards, U.S. Department, (U.S. Government document no. AD56-412), 1 Feb 1954
