This is a valid domain name (remove www)(ai)

    When a user needs to type a domain name, the length of each label is
    omitted and the labels are separated by dots (".").  Since a complete
    domain name ends with the root label, this leads to a printed form which
    ends in a dot.  We use this property to distinguish between:
    
       - a character string which represents a complete domain name
         (often called "absolute").  For example, "poneria.ISI.EDU."
    
       - a character string that represents the starting labels of a
         domain name which is incomplete, and should be completed by
         local software using knowledge of the local domain (often
         called "relative").  For example, "poneria" used in the
         ISI.EDU domain.
    
    Relative names are either taken relative to a well known origin, or to a
    list of domains used as a search list.  Relative names appear mostly at
    the user interface, where their interpretation varies from
    implementation to implementation, and in master files, where they are
    relative to a single origin domain name.  The most common interpretation
    uses the root "." as either the single origin or as one of the members
    of the search list, so a multi-label relative name is often one where
    the trailing dot has been omitted to save typing.[2]