PHP: может ли массив иметь массив в качестве ключа в паре ключ-значение?

Я получаю" Недопустимый тип смещения "для этого массив:

public static $CATS_AND_TYPES = array(

        // Statement Administration
        array( self::CAT_STATEMENT_ADMIN => "Document Administration" ) => array(
            self::TYPE_STATEMENTS_LOADED => "Documents Loaded",
            self::TYPE_STATEMENTS_REMOVED => "Documents Removed"
        ),

        // Cron Jobs
        array( self::CAT_CRON_JOBS => "Cron Jobs" ) => array(
            self::TYPE_CRON_BULLETIN_RUN => "Bulletin Cron Job Ran",
            self::TYPE_CRON_EMAILER_RUN => "Emailer Cron Job Ran",
            self::TYPE_CRON_SURVEY_RUN => "Survey Cron Job Ran",
            self::TYPE_CRON_JOURNEY_RUN => "Journey Cron Job Ran",
            self::TYPE_CRON_DOCUMENT_RUN => "Document Cron Job Ran"
        ),

        // Global Administration
        array( self::CAT_GLOBAL_ADMIN => "Global Administration" ) => array(
            self::TYPE_GLOBAL_MAINTENANCE => "Global Maintenance",
            self::TYPE_GLOBAL_EMAIL_SENDING => "Email Sending"
        ),

        // Email Administration
        array( self::CAT_EMAIL_ADMIN => "Email Administration" ) => array(
            self::TYPE_EMAIL_SENT => "Email Sent",
            self::TYPE_EMAIL_RESENT => "Email Resent",
            self::TYPE_EMAIL_REMOVED => "Email Removed"
        ),

        // DCVs Administration
        array( self::CAT_DCVS_ADMIN => "DCVs Administration" ) => array(
            self::TYPE_DCVS_FLEX_UPDATED => "Flexible Variables Updated",
            self::TYPE_DCVS_GLOBAL_UPDATED => "Global Variables Updated"
        ),

        // Video Administration
        array( self::CAT_VIDEO_ADMIN => "Video Administration" ) => array(
            self::TYPE_VIDEO_ADDED => "Video Added",
            self::TYPE_VIDEO_EDITED => "Video Edited",
            self::TYPE_VIDEO_REMOVED => "Video Removed"
        ),

        // Bulletin Board Administration
        array( self::CAT_BULLETIN_BOARD => "Bulletin Board Administration" ) => array(
            self::TYPE_BULLETIN_DELETED => "Message Deleted",
            self::TYPE_BULLETIN_EDITED => "Message Edited",
            self::TYPE_BULLETIN_ADDED => "Message Added"
        ),

        // User Administration
        array( self::CAT_USER_ADMIN => "User Administration" ) => array(
            self::TYPE_USER_ADDED => "User Added",
            self::TYPE_USER_ADDED_MULTI => "Multiple Users Added",
            self::TYPE_USER_REMOVED => "User Removed",
            self::TYPE_USER_REMOVED_MULTI => "Multiple Users Removed",
            self::TYPE_USER_UPDATED => "User Updated"
        ),

        // Survey Administration
        array( self::CAT_SURVEY_ADMIN => "Survey Administration" ) => array(
            self::TYPE_SURVEY_ADDED => "Survey Added",
            self::TYPE_SURVEY_UPDATED => "Survey Updated",
            self::TYPE_SURVEY_REMOVED => "Survey Removed",
            self::TYPE_SURVEY_REMOVED_MULTI => "Multiple Surveys Removed"
        )
    );

отчасти раздражает создание другого массива просто для того, чтобы определить, что здесь определено в ключах, поэтому мне было интересно, если это было моей проблемой. если это так, я думаю, мне придется сделать ключ- массив значений для идентификаторов категорий и строковых значений.

спасибо! используя в качестве списка вкладок: