An Unkindness of Ravens Fink. When Wexford does a favour for his wife—to look into the disappearance of one of their neighbours' husbands—everything he finds seems to confirm his first inkling: that this is simply another case of a bored middle-aged man having run off with a younger woman. However, when Rodney Williams is found dead, and another local man is stabbed in his car, Wexford finds himself thrown into an investigation involving a militant feministic organisation known as "Arria", who have taken the raven as their symbol. An Unkindness of Ravens An Unkindness of Ravens is a novel by British crime-writer Ruth Rendell.
Collectively exhaustive events Compare this to the concept of a set of mutually exclusive events. In such a set no more than one event can occur at a given time. (In some forms of mutual exclusion only one event can ever occur.) The set of all possible die rolls is both mutually exclusive and collectively exhaustive (i.e., "MECE"). The events 1 and 6 are mutually exclusive but not collectively exhaustive. The events "even" (2,4 or 6) and "not-6" (1,2,3,4, or 5) are collectively exhaustive but not mutually exclusive. In some forms of mutual exclusion only one event can ever occur, whether collectively exhaustive