Union
$$A \cup B =$$
{ Liskov substitution, concrete example, dependency inversion, duel coding, elaboration, interface segregation, interleaving, open-closed, retrieval, single responsibility, spaced practice }
Symmetric Difference
$$A \ominus B =$$
{ Liskov substitution, concrete example, dependency inversion, duel coding, elaboration, interface segregation, interleaving, open-closed, retrieval, single responsibility, spaced practice }
Cartesian Product
$$A \times B =$$
{ (Liskov substitution, concrete example),
(Liskov substitution, duel coding),
(Liskov substitution, elaboration),
(Liskov substitution, interleaving),
(Liskov substitution, retrieval),
(Liskov substitution, spaced practice),
(dependency inversion, concrete example),
(dependency inversion, duel coding),
(dependency inversion, elaboration),
(dependency inversion, interleaving),
(dependency inversion, retrieval),
(dependency inversion, spaced practice),
(interface segregation, concrete example),
(interface segregation, duel coding),
(interface segregation, elaboration),
(interface segregation, interleaving),
(interface segregation, retrieval),
(interface segregation, spaced practice),
(open-closed, concrete example),
(open-closed, duel coding),
(open-closed, elaboration),
(open-closed, interleaving),
(open-closed, retrieval),
(open-closed, spaced practice),
(single responsibility, concrete example),
(single responsibility, duel coding),
(single responsibility, elaboration),
(single responsibility, interleaving),
(single responsibility, retrieval),
(single responsibility, spaced practice) }
SOLID