The package defines the command \perfectcut#1#2 which displays
a bracket <#1||#2>. Its effect is to determine the size of the
bracket depending on the number of nested \perfectcut
(regardless of the contents). The command is intended for use:
In proof theory, for term notations of sequent calculus, In
computer science, for the modeling of abstract machines. The
package also offers a reimplementation of \big, \bigg, etc.,
into arbitrary-size variants.
