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something is a person if it is either Adam or Eve, or if it has a mother. We can express this in a single rule as follows:

person(X) :- (X=adam; X=eve; mother(X, Y)).

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[-] xmunk@sh.itjust.works 6 points 1 week ago

I'll admit I don't speak prolog but doesn't this definition lack a recursive case to ensure that the mother is either Eve or a descendent of Eve? And there should probably be a father case in there as well?

[-] sebastiancarlos@lemmy.sdf.org 8 points 1 week ago* (last edited 1 week ago)

Depends on how you want to define your domain knowledge.

The thing you need to define for sure is the predicate mother/2 (Which has arity 2, or in other words, two arguments). From then on, multiple options are available:

  1. Take mother(X, Y) as an "axiom", and define mother terms for all elements:
mother(abel, eve).
mother(isaac, sarah).
  1. Derive mother(X, Y) from female(X) and parent(X, Y) terms.
mother(X, Y) :- 
  parent(X, Y), 
  female(Y).
  1. Smash the institutional gender power structures and define only parent/2 terms instead of mother/2 and father/2.
[-] silasmariner@programming.dev 6 points 1 week ago

I never saw such a potent combination of gender politics and prolog

[-] bleistift2@sopuli.xyz 4 points 1 week ago* (last edited 1 week ago)

doesn’t this definition lack a recursive case to ensure that the mother is either Eve or a descendent of Eve

We don’t see the definition of mother. It might already encode that Y is a person.

And there should probably be a father case in there as well?

While every person does also have a father, it’s completely redundant, since being a person can fully be described by [Edit: ~~being~~ having] a mother (or being Adam or Eve).

[-] DrDeadCrash@programming.dev 1 points 1 week ago

since being a person can fully be described by being a mother

Can you explain how this is?

[-] bleistift2@sopuli.xyz 1 points 1 week ago

Thanks for catching that. I fixed my comment.

this post was submitted on 03 Jan 2025
43 points (92.2% liked)

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