Another aspect of the lack of integration between roots and complex numbers

[rchillyard]

ExpressionSpec:ExpressionOps:evaluate sqrt 36

Taking the square root of 36 simply returns 6, whereas, ideally, it should return a pair of roots, with values 6 and -6.

[rchillyard]

Conceivably, we could have this return a QuadraticEquation that defines the roots but doesn't pick one over the other.
This needs more thought.