Hmmm??
As both art and public are incredibly contested and fluid terms it seems better to un/define and explore them through practical doing. However, Public as a relationship (of more than one previously unrelated person) and art as an activity (of imaginative creative processes) seem to form the basis of my understanding.
Public and Art bring to mind terms like outside(r) and inside(r), so to release fixed definitions I prefer to imagine and configure expanding and contracting formulations of these terms in relation to process, people and contexts.
how about;
public/art = insideoutsidein x outsideinsideout?
Dan Shipsides, 2009
Dan Shipsides is an artist / Researcher / Lecturer. He is co-leader of the MA Art in Public School of Art and Design / Interface University of Ulster.