Contrapose back on conditional chains in LG?

holden.valentine

Does anybody have any tips on executing this skill or is able to point me in the right direction? Thanks.

yunonsie

Following. I usually write out the contrapositive chain quickly, but curious how to do this too.

kingfish743-1

A-->B-->C-->D

Whatever variable is negated after your original chain is established, start at that point and run it backwards (right to left), negating as you go. Ignore everything to the right of the negated variable.

If C is negated, then you now know -B, -A. Because the variable C is negated in this example, you learn, per the contrapositive, that B and A are also negated; however, you cannot infer anything about D. Less confusion than having the entire contrapositive written out, IMO. Whatever variable is reversed (positive to negative or negative to positive )in the logic chain, start at that point and reverse(positive to negative or negative to positive) everything going backwards in the logic chain.

If original logic chain in an IN/OUT is A--> -B --> C --> -D --> E and D is "IN", then, starting at D, you run the logic chain backwards to find -C, B, -A. So, you'd have IN (D,B) and OUT (C, A); you'd know nothing about E.

Is this what you were looking for or did I misunderstand your question? Hope this is somewhat helpful.