Union
$$A \cup B =$$
{ beauty, concrete operational, crown, formal operational, foundation, glory, kingdom, mercy, pre-operational, sensorimotor, severity, understanding, victory, wisdom }
Symmetric Difference
$$A \ominus B =$$
{ beauty, concrete operational, crown, formal operational, foundation, glory, kingdom, mercy, pre-operational, sensorimotor, severity, understanding, victory, wisdom }
Cartesian Product
$$A \times B =$$
{ (beauty, concrete operational),
(beauty, formal operational),
(beauty, pre-operational),
(beauty, sensorimotor),
(crown, concrete operational),
(crown, formal operational),
(crown, pre-operational),
(crown, sensorimotor),
(foundation, concrete operational),
(foundation, formal operational),
(foundation, pre-operational),
(foundation, sensorimotor),
(glory, concrete operational),
(glory, formal operational),
(glory, pre-operational),
(glory, sensorimotor),
(kingdom, concrete operational),
(kingdom, formal operational),
(kingdom, pre-operational),
(kingdom, sensorimotor),
(mercy, concrete operational),
(mercy, formal operational),
(mercy, pre-operational),
(mercy, sensorimotor),
(severity, concrete operational),
(severity, formal operational),
(severity, pre-operational),
(severity, sensorimotor),
(understanding, concrete operational),
(understanding, formal operational),
(understanding, pre-operational),
(understanding, sensorimotor),
(victory, concrete operational),
(victory, formal operational),
(victory, pre-operational),
(victory, sensorimotor),
(wisdom, concrete operational),
(wisdom, formal operational),
(wisdom, pre-operational),
(wisdom, sensorimotor) }
Cognition