MutableMatrix _ Sequence = Thing -- assignment to an element of a mutable matrix

• Operator: _

• Usage:

  f_(i,j) = r

• Inputs:
  • f, a mutable matrix
  • a pair (i,j) of integers
  • r, a thing
• Consequences:

  • the (i,j) entry of f is replaced by the ring element r

i1 : R = QQ[a..d]

o1 = R

o1 : PolynomialRing

i2 : f = mutableMatrix vars R

o2 = | a b c d |

o2 : MutableMatrix

i3 : f_(0,2)

o3 = c

o3 : R

i4 : f_(0,2) = 7*c^2

       2
o4 = 7c

o4 : R

i5 : f

o5 = | a b 7c2 d |

o5 : MutableMatrix