Barua, RanaMaitra, A2011-07-062011-07-062007Procedings of Indian Academy of sciences(Mathematical sciences),V117,2,P205-211http://hdl.handle.net/10263/2199enBorel sets of additive classesBaire propertyLevy-solovay modelGandy-harrington topologyBorel hierarchies in finite products of polish spacesArticle