Anchor: Because he has fought many times to keep or take mares, he is a formidable and vicious opponent, one that an imported, tamed stud can rarely best.
Entailed: He is a formidable and vicious opponent.
Contradiction: He is an easy opponent.
Contradiction: The girls are on an airplane.
Contradiction: A cruise liner blocks the horizon view from the beach.
Contradiction: Mexicans make less money. 
Contradiction: They didn't know how many people were left.