def name_relative_to(parent_abspath, child_abspath):
    """ Determine the relative name of a child path with respect to a parent
    system.

    Args
    ----
    parent_abspath : str
        Asbolute path of the parent.

    child_abspath : str
        Absolute path of the child.

    Returns
    -------
    str
        Name of the child relative to the parent.
    """
    start = len(parent_abspath)+1 if parent_abspath else 0
    return child_abspath[start:].split('.', 1)[0]