With no explanation, label text_A→text_B with either "not-entailed" or "entailed".
text_A: Just a quick message to follow up on the email that I sent you recently inviting you to speak at our forthcoming congress , Risk 2001 Australia , which is taking place in Sydney on 20 & 21 August 2001 .
text_B: The sending did not happen
not-entailed.