Anchor: A band is playing on stage, and two members are singing.
Entailed: A band is performing a show.
Contradiction: A one man band is playing.
Contradiction: The structure of stock options has been largely left unnoticed. 
Contradiction: Everything about the IPO process works against the market's efficient operation.
Contradiction: The dogs are sleeping
Contradiction: Martha is the CEO of a company named Omnimedia.