Database: academic
Question: return me the keyword, which have been contained by the most number of papers by " H. V. Jagadish " .
SQL:
SELECT t1.keyword FROM publication_keyword AS t5 JOIN keyword AS t1 ON t5.kid  =  t1.kid JOIN publication AS t3 ON t3.pid  =  t5.pid JOIN writes AS t4 ON t4.pid  =  t3.pid JOIN author AS t2 ON t4.aid  =  t2.aid WHERE t2.name  =  "H. V. Jagadish" GROUP BY t1.keyword ORDER BY COUNT ( DISTINCT t3.title ) DESC LIMIT 1;