built in compound operators: drop-above

drop-above:
    description:
        drop-above[t] sp
        drop all kets with coeff > t from the given superposition

    examples:
        drop-above[1.99] (-1 |a> + 0|b> + |c> + 2|d> + 3|e> + 4|f>)
            - |a> + 0|b> + |c>

    see also:
        drop, drop-below, sdrop