@prefix log: <http://www.w3.org/2000/10/swap/log#>.
@prefix : <https://eyereasoner.github.io/ns#>.

# facts
:Socrates a :Human.

# proof by contradiction
{
    ?X a :Human.
    {
        ?X a :Human.
        { ?X a :Human } => { ?X a :Mortal }.
        { ?X a :Mortal } => false.
    } log:satisfiable false.
} => {
    ?X a :Mortal.
}.
