Return the names of artists and the themes of their exhibitions that had a ticket price higher than average.
return exhibitions ;return ticket prices of #1 ;return average of #2 ;return #1 where #2 is  higher than #3 ;return artists of #4 ;return names of #5 ;return themes of #4 ;return #6 ,  #7
['select', 'project', 'aggregate', 'comparative', 'project', 'project', 'project', 'union']