$\}$

$AC$

$CGH$

$CGI$

$\{BH$

$(AG{)}^{+}$

result $=AG$

result and $AB$

result $=$ABCGH

and CGsubeAGBC

result $=$ABCGHI $(CG$I and CGsubeAGBCH $)$

Is $AG$ a candidate key?

Is AG a super key?

Does $AGR?==$ Is $(AG{)}^{+}$supeR

Is any subset of $AG$ a superkey?

Does $AR?==$ Is $(A{)}^{+}$supeR

Does $GR?==$ Is $(G{)}^{+}$supeR