Anchor: However, the achievement did not greatly impress his fellow mathematicians.
Entailed: His achievement didn't impress his colleagues. 
Contradiction: The achievement greatly impressed the mathematicians. 
Contradiction: The fumes are a terrible idea, and I couldn't get in there at all.
Contradiction: A soccer player leaves the ground to kick a ball.
Contradiction: A man is sleeping in the chair.
Contradiction: Mr. Julius Hersheimmer's supper party was an historical event in catering circles.