1Z0-497 Web TestEngine demo

In this SQL statement, what is the partitioning criteria?

CREATE TABLE books_part
PARTITION BY RANGE (cell_id) (
PARTITION p0l VALUES LESS THAN (2),
PARTITION p02 VALUES LESS THAN (3) ,
. . .
PARTITION pl4 VALUES LESS THAN (15),
PARTITION pl5 VALUES LESS THAN (16),
PARTITION pl6 VALUES LESS THAN (MAXVALUE)
)
AS SELECT * FROM books;