Anchor: Only a few installations have required the relocation of the air preheater.
Entailed: The relocation of the air preheater was only required in a few installations.
Contradiction: The relocation of the air preheater was not required in any of the installations.
Contradiction: The skater is sleeping.
Contradiction: We have tons of Mobil. 
Contradiction: The car is driving through a car wash.
Contradiction: A dog chasing another dog with a ball.