For synchronizing this calendar with your own software, see the instructions below.

• Don't use an account with write access to synchronize with the Mac OS-X calendar program (it seems to delete all events)! The Google Calendar app on Android and iPhone iOS seem to be fine, and if you don't have write access, then everything is fine.
• To get more information about an event, click on the title.
• These are three calendars replacing the old single events calendar. The old calendar has been renamed as "Events ...", and the new calendars are "Seminar ..." and "Leiden General Mathematics Colloquium".
• Please add your own seminar and relevant events to "Events ...". To get write access, create a Google account and let me know the email address of the Google account.
• For just the seminar, see the seminar web page.
• For just the colloquium, see the colloquium web page.