▁coh om ology , ▁introdu cing ▁what ▁is ▁now ▁known ▁as ▁the ▁Ze eman ▁spectral ▁sequence . ▁This ▁was ▁studied ▁by ▁Cl int ▁McC r ory ▁in ▁his ▁ 1 9 7 2 ▁Bran de is ▁th esis ▁following ▁a ▁suggestion ▁of ▁Dennis ▁S ull ivan ▁that ▁one ▁make ▁" a ▁general ▁study ▁of ▁the ▁Ze eman ▁spectral ▁sequence ▁to ▁see ▁how ▁singular ities ▁in ▁a ▁space ▁perturb ▁Po inc ar é ▁du ality ". ▁This ▁in ▁turn ▁led ▁to ▁the ▁discovery ▁of ▁intersection ▁hom ology ▁by ▁Robert ▁Mac Ph erson ▁and ▁Mark ▁G ores ky ▁at ▁Brown ▁University ▁where ▁McC r ory ▁was ▁appointed ▁in ▁ 1 9 7 4 . ▁ ▁From ▁ 1 9 7 6 ▁to ▁ 1 9 7 7 ▁he ▁was ▁the ▁Don eg all ▁L ect urer ▁in ▁Mathemat ics ▁at ▁Tr inity ▁College ▁Dublin . ▁ ▁Ze eman ▁is ▁known ▁among ▁the ▁wider ▁scientific ▁public ▁for ▁his ▁contribution ▁to , ▁and ▁spread ing ▁aw aren ess ▁of ▁cat ast rop he ▁theory , ▁which ▁was ▁due ▁initially ▁to ▁another ▁top ologist , ▁René ▁Thom , ▁and ▁for ▁his ▁Christmas ▁lect ures ▁about ▁mathematics ▁on ▁television ▁in ▁ 1 9 7 8 . ▁He ▁was ▁especially ▁active ▁encourag ing ▁the ▁application ▁of ▁mathematics , ▁and ▁cat ast rop he ▁theory ▁in ▁particular , ▁to ▁bi ology ▁and ▁behaviour al ▁sciences . ▁ ▁Early ▁life ▁Ze eman ▁was ▁born ▁in ▁Japan ▁to ▁a ▁Dan ish ▁father , ▁Christian ▁Ze eman , ▁and ▁a ▁British ▁mother . ▁They