Chapter 9.5, Problem 2E

ch of these relations on the set of all people are equivalence relations? Determine the properties of an equivalence relation that the others lack.

a) {(a.b) |aandbare the same age}

b) {(a.b) |aandbhave the same parents}

c) {(a,b) |aandbshare a common parent}

d) {(a,b) |aandbhave met}

e) {(a,b) |aandbspeak a common language}