In mathematics, an index set is another name for a function domain. A collection indexed by I, often written Ai for i in I (can be said 'for irunning overI ') is in effect a function A(i) into some codomain.
Index sets are often used in sums (sigma notation) and other such operations; and are common when the Ai are themselves sets rather than numbers, in indexed intersections and unions.
Families
A family is another description of an indexed collection, often used of a family of sets. In contrast to a set of elements, a family can contain an element more than once (that is, the underlying function need not be injective).
Examples
An n-tuple can be considered as a family over the finite index set {1, 2, ..., n}
More generally, a functor can be considered as giving rise to an indexed family of objects in a categoryD, indexed by another category C, and related by morphisms depending on two indices.
The set-up index key (part #46250) is used in the articulator for positional orientation of the edentulous lower model, according to the Bonwill Triangle.
Instead, use the set-up index key with the "Splitex" magnetic adapter plate to mount it directly to the magnetic plate on the upper arm of the articulator.
Divide the distance between the upper and lower mucolabial folds in half to determine the setting of the index on the symphesis fork.
Feeds |
Contact