I came across this logic exercise, and I would like to confirm if my solutions are valid.
Here is the setup:
Fact base: {A}
Rule base:
R1: A → B
R2: B → C
R3: E → D
Goal: Add one rule such that D can be derived using forward chaining, but cannot be derived using backward chaining.
I found two possible rules:
True → E
¬X → E (where X is not in the fact base)
Can someone confirm whether these rules satisfy the condition? If not, what is the correct rule, and how can it be logically derived?
Thank you in advance for your help.
