PHL246H1 Lecture Notes - Collectively Exhaustive Events, Empty Set
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The symbol p" denotes the union of all members of p. if b, c, d, are all the members of p, then p = B c d formally it is defined as: p = {x: x s for some s p}. The set {{parisa, seya}, {franz}} is a partition of t, and so are {{parisa}, {seya}, {franz}} and { , t}. Consider the set s of all students enrolled in phl 246. Show that the following set is a partition of s by establishing that its members are mutually exclusive and jointly exhaustive: {{x s: x is younger than 20 years}, {x s: x is at least 20 years, but less than 30 years}, {x s: x is older than 30 years}} (2 points) Show that the empty set is a member of a, a. (hint: use (i) and (ii). ) (1. 5 points)