@article {2013, title = {Quadratic cohomology}, year = {2013}, note = {24 pages}, publisher = {SISSA}, abstract = {We study homological invariants of smooth families of real quadratic forms as\r\na step towards a \"Lagrange multipliers rule in the large\" that intends to\r\ndescribe topology of smooth vector functions in terms of scalar Lagrange\r\nfunctions.}, author = {Andrei A. Agrachev} }