Union
$$A \cup B =$$
{ Inheritance, charity, devotion, fasting, pilgrimage, prayer, purity, selection, struggle, time, variation }
Symmetric Difference
$$A \ominus B =$$
{ Inheritance, charity, devotion, fasting, pilgrimage, prayer, purity, selection, struggle, time, variation }
Difference
$$B - A =$$
{ charity, devotion, fasting, pilgrimage, prayer, purity, struggle }
Cartesian Product
$$A \times B =$$
{ (Inheritance, charity),
(Inheritance, devotion),
(Inheritance, fasting),
(Inheritance, pilgrimage),
(Inheritance, prayer),
(Inheritance, purity),
(Inheritance, struggle),
(selection, charity),
(selection, devotion),
(selection, fasting),
(selection, pilgrimage),
(selection, prayer),
(selection, purity),
(selection, struggle),
(time, charity),
(time, devotion),
(time, fasting),
(time, pilgrimage),
(time, prayer),
(time, purity),
(time, struggle),
(variation, charity),
(variation, devotion),
(variation, fasting),
(variation, pilgrimage),
(variation, prayer),
(variation, purity),
(variation, struggle) }
Seven pillars of Ismailism