Anchor: We assume that the two firms share the market equally, each delivering a random half of the mail.
Entailed: Equal market share is assumed for the two companies.
Contradiction: One company is assumes to hold all the market share.
Contradiction: Three women sit.
Contradiction: People are attending an event.
Contradiction: A man is riding a bicycle with the flowers in his mouth.
Contradiction: some people hiking thru a forest