Operations On Families
Index sets are often used in sums and other similar operations. For example, if (ai)i∈I is a family of numbers, the sum of all those numbers is denoted by
When (Ai)i∈I is a family of sets, the union of all those sets is denoted by
Likewise for intersections and cartesian products.
Read more about this topic: Indexed Family
Famous quotes containing the words operations and/or families:
“A sociosphere of contact, control, persuasion and dissuasion, of exhibitions of inhibitions in massive or homeopathic doses...: this is obscenity. All structures turned inside out and exhibited, all operations rendered visible. In America this goes all the way from the bewildering network of aerial telephone and electric wires ... to the concrete multiplication of all the bodily functions in the home, the litany of ingredients on the tiniest can of food, the exhibition of income or IQ.”
—Jean Baudrillard (b. 1929)
“The authoritarian child-rearing style so often found in working-class families stems in part from the fact that parents see around them so many young people whose lives are touched by the pain and delinquency that so often accompanies a life of poverty. Therefore, these parents live in fear for their children’s future—fear that they’ll lose control, that the children will wind up on the streets or, worse yet, in jail.”
—Lillian Breslow Rubin (20th century)