Editing Scale invariance (section)

===Projective geometry===
The idea of scale invariance of a monomial generalizes in higher dimensions to the idea of a [[homogeneous polynomial]], and more generally to a [[homogeneous function]]. Homogeneous functions are the natural denizens of [[projective space]], and homogeneous polynomials are studied as [[projective varieties]] in [[projective geometry]].  Projective geometry is a particularly rich field of mathematics; in its most abstract forms, the geometry of [[scheme (mathematics)|schemes]], it has connections to various topics in [[string theory]].