@article {2012,
	title = {Systems of Quadratic Inequalities},
	journal = {Proceedings of the London Mathematical Society, Volume 105, Issue 3, September 2012, Pages 622-660},
	number = {arXiv:1012.5731;},
	year = {2012},
	publisher = {SISSA},
	abstract = {We present a spectral sequence which efficiently computes Betti numbers of a
closed semi-algebraic subset of RP^n defined by a system of quadratic
inequalities and the image of the homology homomorphism induced by the
inclusion of this subset in RP^n. We do not restrict ourselves to the term E_2
of the spectral sequence and give a simple explicit formula for the
differential d_2.},
	doi = {DOI: 10.1112/plms/pds010},
	url = {http://hdl.handle.net/1963/7072},
	author = {Andrei A. Agrachev and Antonio Lerario}
}
