' s ▁ 1 8 2 8 ▁work ▁from ▁William ▁Hop kins ▁in ▁ 1 8 4 5 . ▁ ▁In ▁ 1 8 7 1 ▁N . ▁M . ▁Ferr ers ▁assemble d ▁The ▁Mathemat ical ▁Pap ers ▁of ▁the ▁late ▁George ▁Green ▁for ▁publication . ▁ ▁Green ' s ▁work ▁on ▁the ▁motion ▁of ▁waves ▁in ▁a ▁canal ▁( result ing ▁in ▁what ▁is ▁known ▁as ▁Green ' s ▁law ) ▁anticip ates ▁the ▁W KB ▁approximation ▁of ▁quantum ▁mechan ics , ▁while ▁his ▁research ▁on ▁light - w aves ▁and ▁the ▁properties ▁of ▁the ▁A ether ▁produced ▁what ▁is ▁now ▁known ▁as ▁the ▁C auch y - Green ▁tensor . ▁Green ' s ▁theorem ▁and ▁functions ▁were ▁important ▁tools ▁in ▁classical ▁mechan ics , ▁and ▁were ▁re vised ▁by ▁Schw inger ' s ▁ 1 9 4 8 ▁work ▁on ▁elect rod ynam ics ▁that ▁led ▁to ▁his ▁ 1 9 6 5 ▁Nobel ▁prize ▁( shared ▁with ▁Fe yn man ▁and ▁Tom on aga ). ▁Green ' s ▁functions ▁later ▁also ▁proved ▁useful ▁in ▁anal ys ing ▁super con duct ivity . ▁On ▁a ▁visit ▁to ▁Not ting ham ▁in ▁ 1 9 3 0 , ▁Albert ▁Ein stein ▁commented ▁that ▁Green ▁had ▁been ▁ 2 0 ▁years ▁ahead ▁of ▁his ▁time . ▁The ▁theoretical ▁phys ic ist ▁Julian ▁Schw inger ▁who ▁used ▁Green ' s ▁functions ▁in ▁his ▁ground - bre aking ▁works , ▁published ▁a ▁t ribute ▁entitled ▁" The ▁Green ing ▁of ▁Quant um ▁Field ▁Theory