Union
$$A \cup B =$$
{ Liskov substitution, dependency inversion, interface segregation, memorization, note taking, open-closed, reading, single responsibility, testing, time management }
Symmetric Difference
$$A \ominus B =$$
{ Liskov substitution, dependency inversion, interface segregation, memorization, note taking, open-closed, reading, single responsibility, testing, time management }
Difference
$$A - B =$$
{ Liskov substitution, dependency inversion, interface segregation, open-closed, single responsibility }
Cartesian Product
$$A \times B =$$
{ (Liskov substitution, memorization),
(Liskov substitution, note taking),
(Liskov substitution, reading),
(Liskov substitution, testing),
(Liskov substitution, time management),
(dependency inversion, memorization),
(dependency inversion, note taking),
(dependency inversion, reading),
(dependency inversion, testing),
(dependency inversion, time management),
(interface segregation, memorization),
(interface segregation, note taking),
(interface segregation, reading),
(interface segregation, testing),
(interface segregation, time management),
(open-closed, memorization),
(open-closed, note taking),
(open-closed, reading),
(open-closed, testing),
(open-closed, time management),
(single responsibility, memorization),
(single responsibility, note taking),
(single responsibility, reading),
(single responsibility, testing),
(single responsibility, time management) }
SOLID