Three more innovations (DFT, LCAO, and Gaussian-orbitals) were introduced in the mid-20th century to alleviate this extreme cost. Two pioneers (of many) Walter Kohn and John Pople were awarded the Nobel Prize in Chemistry in 1998 for their contributions. Walter Kohn was awarded for this work on developing DFT, using functionals on 1-body densities to capture many-body correlations. This in principle leads to a reduction in memory to: