1)From Oracle Universal Installer: In OUI select installed products and click on list and expand, you will see a list of options installed in database.
You have to use OUI to check whether Oracle Secure Enterprise Search is installed or not.
TIP: Start Oracle Universal Installer from your system prompt (UNIX) with the following command:
./runInstaller
2)From v$option:
SQL> set pages 100
SQL> select * from v$option;
PARAMETER                                                        VALUE
—————————————————————- —–
Partitioning                                                     TRUE
Objects                                                          TRUE
Real Application Clusters                                        FALSE
Advanced replication                                             TRUE
Bit-mapped indexes                                               TRUE
Connection multiplexing                                          TRUE
Connection pooling                                               TRUE
Database queuing                                                 TRUE 
Incremental backup and recovery                                  TRUE
Instead-of triggers                                              TRUE
Parallel backup and recovery                                     TRUE
Parallel execution                                               TRUE
Parallel load                                                    TRUE
Point-in-time tablespace recovery                                TRUE
Fine-grained access control                                      TRUE
Proxy authentication/authorization                               TRUE