The Less is More... group is a focus on minimalism with a subject. Often Minimalism focuses on removing all context from a photograph, abstractions are welcome here, just be sure that the subject is identifiable.
Everything that "doesn't matter" is stripped out, leaving only the focus, whether it be a shape or a color or an emotion. Simple in form (usually) but may be very complex in nature or in detail.
The "finest" examples of minimalism encompass all three to a degree - a clarity of imagery - a purity almost... nothing hidden, just an image laid bare.