today
	finish depth-3 homogeneous lbs
	polynomial identity testing
depth-3 homogeneous
	recap
	lb for partial derive space of determinant
PIT
	given polynomial is it zero
	PIT in RP
	Q. PIT in P?
	def: hitting set
	rmk:
		small explicit hitting sets => PIT \in P
		large explicit hitting sets exist, via schwartz-zippel
		small hitting sets exist, via prob-method
		hitting sets =~ lbs
	q. hitting sets for depth-3 hom?
		given small top-fan-in depth-3, you know it isn't the determinant
	def of sparse
	white-box vs black-box
	thm statement
		idea: hash to one variable
			use univariate interpolation