Hillary is a girl. Hillary is not a blond girl. Hillary is not a girl. Mary ran quickly. No tall politician is pregnant.
Every politician is non-pregnant.
Two sentences are equivalent if they entail each other. Tina is tall and thin Tina is both tall and thin Tina is blond or both tall and thin Tina is both blond or tall and blond or thin a. Give more examples for equivalent sentences. Give a semantics for both that captures the first equivalence above and show that under the semantics you have given in exercise 2, also the second equivalence is accounted for compositionally. Two sentences are contradictory if whenever one of them denotes true the other denotes false . The following sentences are structurally ambiguous.