The following example uses IS [NOT] UNTIL_CLOSED in the PPI partitioning expression to check whether or not the ending bound of a transaction time column is UNTIL_CLOSED.
CREATE TABLE TESTUC (A INTEGER, B PERIOD (TIMESTAMP (6) WITH TIME ZONE) NOT NULL AS TRANSACTIONTIME, C INTEGER) PRIMARY INDEX (A) PARTITION BY CASE_N (END (b) IS UNTIL_CHANGED, END (b) IS NOT UNTIL_CHANGED, UNKNOWN);