Symbol _ Thing -- index variable

Synopsis

Operator: _
Usage:

s_v
Inputs:
- s, a symbol
- v, a thing
Outputs:
- an indexed variable

Description

The subscript can be anything, even a mutable object. Often, the subscripts are numbers or sequences. Sequences usually print nicer than lists.

i1 : x_(1,3)

o1 = x
      1,3

o1 : IndexedVariable

i2 : x_{1,3}

o2 = x
      {1, 3}

o2 : IndexedVariable

Indexed variables can be used for ring variables.

i3 : R = ZZ[x_(1,1)..x_(2,3),y_a..y_f]

o3 = R

o3 : PolynomialRing

i4 : gens R

o4 = {x   , x   , x   , x   , x   , x   , y , y , y , y , y , y }
       1,1   1,2   1,3   2,1   2,2   2,3   a   b   c   d   e   f

o4 : List

Ways to use this method:

Symbol _ Thing -- index variable