Family-Rule: If a message is from someone who belongs-to the family of Fred then the message is important. Daisy-Rule: If a message is from Daisy then the message is not important. Emergency-Rule: If a message is a notification of an emergency then the message is important. Daisy-Rule overrides Family-Rule. Emergency-Rule overrides Daisy-Rule. Emergency-Rule overrides Family-Rule. If there is an illness of someone who belongs-to the family of Fred then the illness is an emergency. Betty belongs-to the family of Fred. Daisy belongs-to the family of Fred. Item19 is a message that is from Betty. Item20 is a message that is from Daisy. Item115 is a message that is from Daisy. Item115 is a message that is a notification of an illness of Daisy.