math 213
posted by susan .
Tell whether each of the following is true for all sets
A, B If false, give a counterexample.
a. AB= A0 (with slashed O)
b. AUB (with line over AUB) = AUB (with line over A and a line over B)

a. true
b. false
U = {1,2,3,4,5}
A = {1,2,3}
B = {2,4,5}
A' = {4,5}
B' = {1,3}
(AUB)' = {}
A'UB' = {1,3,4,5}
However A' ∩ B' = {}