Is matter real?

Apparently, certain aspects of matter (mass, electric charge, etc.) are real and are not associated with a wave function.

If so, do they exist as matter or waves even without an observer?

Does decoherence occur without an observer?

This meeting will explore the Einstein's comment paraphrased as follows:

Does the moon exist as matter or waves if we are not observing it?

The attendee is encouraged to be familiar with the double-slit experiment of quantum physics before participating in this meeting.