Union
$$A \cup B =$$
{ Decision Theory, Logic, Mathematics, Statistics, Systems Theory, Theoretical Computer-Science, interpret, organize, select, stimulus }
Symmetric Difference
$$A \ominus B =$$
{ Decision Theory, Logic, Mathematics, Statistics, Systems Theory, Theoretical Computer-Science, interpret, organize, select, stimulus }
Difference
$$A - B =$$
{ Decision Theory, Logic, Mathematics, Statistics, Systems Theory, Theoretical Computer-Science }
Cartesian Product
$$A \times B =$$
{ (Decision Theory, interpret),
(Decision Theory, organize),
(Decision Theory, select),
(Decision Theory, stimulus),
(Logic, interpret),
(Logic, organize),
(Logic, select),
(Logic, stimulus),
(Mathematics, interpret),
(Mathematics, organize),
(Mathematics, select),
(Mathematics, stimulus),
(Statistics, interpret),
(Statistics, organize),
(Statistics, select),
(Statistics, stimulus),
(Systems Theory, interpret),
(Systems Theory, organize),
(Systems Theory, select),
(Systems Theory, stimulus),
(Theoretical Computer-Science, interpret),
(Theoretical Computer-Science, organize),
(Theoretical Computer-Science, select),
(Theoretical Computer-Science, stimulus) }