compound context seq fn: find-inverse

find-inverse:
    description:
        find-inverse[op1, op2, ...]
        find-inverse[*]
        learn the inverses for the given operators
        since operators are directed links in a graph, we use this function to learn the inverse links

    examples:
        load fred-sam-friends.sw
        find-inverse[friends]
        dump
            ------------------------------------------
            |context> => |Fred Sam friends>

            friends |Fred> => |Jack> + |Harry> + |Ed> + |Mary> + |Rob> + |Patrick> + |Emma> + |Charlie>
            age |Fred> => |32>

            friends |Sam> => |Charlie> + |George> + |Emma> + |Jack> + |Robert> + |Frank> + |Julie>
            age |Sam> => |34>

            inverse-friends |Jack> => |Fred> + |Sam>

            inverse-friends |Harry> => |Fred>

            inverse-friends |Ed> => |Fred>

            inverse-friends |Mary> => |Fred>

            inverse-friends |Rob> => |Fred>

            inverse-friends |Patrick> => |Fred>

            inverse-friends |Emma> => |Fred> + |Sam>

            inverse-friends |Charlie> => |Fred> + |Sam>

            inverse-friends |George> => |Sam>

            inverse-friends |Robert> => |Sam>

            inverse-friends |Frank> => |Sam>

            inverse-friends |Julie> => |Sam>
            ------------------------------------------

    see also: