NOT.4:2 - Problem

How can a notation provide useful transformations whose applicability and preserved consequences remain understandable when the expression or its context changes?

A visually simpler expression can hide a necessary distinction. Reusing a name can bind an occurrence that previously referred elsewhere; combining repeated signs can combine two actions that were meant to occur separately. A valid equality may hold only under a local assumption. Without those conditions, a transformation can preserve one displayed answer while changing the work it is supposed to support.