N.Y. Local Finance Law § 82.00

§ 82.00 Twenty day period of limitation. After the publication of a\nresolution, summary of such resolution or certificate together with such\na notice, the validity of the obligations authorized thereby may be\ncontested only if:\n 1. Such obligations were authorized for an object or purpose for which\nthe municipality, school district or district corporation is not\nauthorized to expend money, or\n 2. The provisions of law which should have been complied with at the\ndate of the publication of such resolution, summary of such resolution\nor certificate were not substantially complied with, and an action, suit\nor proceeding contesting such validity is commenced within twenty days\nafter such publication, or\n 3. Such obligations were authorized in violation of the provisions of\nthe constitution.\n