Sec. 4. (a) Real property may be assessed, or its assessed value increased, for a prior year under this chapter only if the notice required by section 1 of this chapter is given within three (3) years after the assessment date for that prior year.
(b) With respect to real property which is owned by a bona fide purchaser without knowledge, no lien attaches for any property taxes which result from an assessment, or an increase in assessed value, made under this chapter for any period before his purchase of the property.