Celebratio Mathematica

Cathleen Morawetz

Happy 91st, Cathleen Synge Morawetz

by Allyn Jackson

Photo from the AMS archives

Cath­leen Synge Mor­awetz is a le­gendary and be­loved fig­ure in math­em­at­ics. Renowned for her strik­ing work in ana­lys­is, she has been an in­spir­a­tion to many in the field, par­tic­u­larly to wo­men, as well as a lead­er in the AMS and in the sci­entif­ic pro­fes­sion more broadly. Her 91st birth­day, which oc­curs in May of this year, is a fit­ting time to pay trib­ute to her life.

Her great-uncle was John Mil­ling­ton Synge, the Ir­ish play­wright best known for Play­boy of the West­ern World, which caused ri­ots when it was first per­formed in 1907. Her fath­er was John Lighton Synge, an Ir­ish math­em­atician who had a long ca­reer at the Uni­versity of Toronto; her moth­er also had some train­ing in math­em­at­ics. When Cath­leen Mor­awetz re­ceived the AMS Steele Prize for Life­time Achieve­ment in 2004, she cred­ited her fath­er with in­stilling the ideal of in­tel­lec­tu­al achieve­ment and her moth­er with in­stilling am­bi­tion, which, Mor­awetz com­men­ted, was “at the time very un­lady­like.”

On the vari­ous oc­ca­sions when Mor­awetz has dis­cussed her long ca­reer, 1 she has put the em­phas­is not so much on her­self but on the people around her who helped her suc­ceed. Among these was Cecil­ia Krieger, who fled Po­land dur­ing World War I and earned a Ph.D. in math­em­at­ics at the Uni­versity of Toronto, later be­com­ing a pro­fess­or there. At a cru­cial mo­ment in Cath­leen’s fi­nal year as a math­em­at­ics ma­jor at Toronto, Krieger en­cour­aged Cath­leen to at­tend gradu­ate school and prom­ised to find fund­ing.

Krieger came through on the prom­ise, and Cath­leen be­came a gradu­ate stu­dent at New York Uni­versity. There were few wo­men in the doc­tor­al pro­gram, but the at­mo­sphere was sup­port­ive, partly be­cause of the in­flu­ence of Richard Cour­ant: He had been a strong ment­or for Emmy No­eth­er in Göttin­gen and con­tin­ued to en­cour­age wo­men in math­em­at­ics after he had emig­rated to New York. One of Mor­awetz’s first ser­i­ous math­em­at­ic­al un­der­tak­ings was the edit­ing of the now-clas­sic book Su­per­son­ic Flow and Shock Waves (1948) by Cour­ant and Kurt Friedrichs. Mor­awetz said that, des­pite her ju­ni­or status, she had stand­ing with the two pro­fess­ors be­cause she could cor­rect their Eng­lish. Edit­ing this book was one of her form­at­ive ex­per­i­ences in math­em­at­ics.

Cour­ant was force­ful and out­go­ing, while Friedrichs was shy and a bit with­drawn. Mor­awetz worked well with both. She flour­ished in the stim­u­lat­ing at­mo­sphere of what later came to be called the Cour­ant In­sti­tute of Math­em­at­ic­al Sci­ences, which drew no bor­ders between pure and ap­plied math­em­at­ics. She was hooked by prob­lems of tran­son­ic flow through con­tact with Friedrichs, who be­came her thes­is ad­visor, and with Lip­man Bers. The sup­port of Cour­ant was cru­cial as Mor­awetz fol­lowed a very non­stand­ard ca­reer path while she bore and raised four chil­dren. She earned her Ph.D. in 1951 and, after a postdoc at the Mas­sachu­setts In­sti­tute of Tech­no­logy, she re­turned to the Cour­ant In­sti­tute as a fac­ulty mem­ber in 1955 and re­mained there for the rest of her ca­reer. She con­tin­ued to draw in­spir­a­tion from those around her at the Cour­ant In­sti­tute, learn­ing about prob­lems in mag­neto­hydro­dynam­ics from Har­old Grad and about wave propaga­tion from Joseph Keller.

Asked wheth­er she is a prob­lem solv­er or a the­ory build­er, Mor­awetz replied, “I am an ap­plied math­em­atician who proves the­or­ems to solve prob­lems.” She has taste both for the math­em­at­ics and for the choice of prob­lems from oth­er areas. One gets a sense of this taste from two of her ex­pos­it­ory art­icles. The first is the writeup of her 1981 AMS Gibbs Lec­ture, “The math­em­at­ic­al ap­proach to the son­ic bar­ri­er” (Bul­let­in of the AMS, March 1982). The art­icle provides clear, down-to-earth ex­plan­a­tions of the phys­ics and en­gin­eer­ing of air foil design, with a math­em­atician’s view­point of try­ing to un­der­stand what’s go­ing on at the deep­est level and to nail down the de­tails with proof. The oth­er art­icle is her Re­tir­ing AMS Pres­id­en­tial Ad­dress “Math­em­at­ics to the res­cue” (No­tices, Janu­ary 1999). This piece puts the spot­light on a few out­stand­ing prob­lems — weath­er pre­dic­tion, mo­lecu­lar struc­ture, and tran­son­ic flow — and throws the math­em­at­ic­al as­pects in­to sharp re­lief. Mor­awetz moves seam­lessly from non­tech­nic­al and in­sight­ful present­a­tions of the phys­ics, en­gin­eer­ing, and math­em­at­ics to en­ter­tain­ing asides about the people in­volved. Both art­icles give a sense of her deep know­ledge, as well as her im­mense charm and hu­mor.

Mor­awetz is the first and only wo­man to have re­ceived the AMS Steele Prize for Life­time Achieve­ment (2004); the same can be said for her re­ceiv­ing the AMS-SIAM Birk­hoff Prize in Ap­plied Math­em­at­ics (2006). She is also the first and only wo­man math­em­atician to have re­ceived the U.S. Na­tion­al Medal of Sci­ence (1998). In ad­di­tion to a term as AMS pres­id­ent (1995–1996), Mor­awetz has served the So­ci­ety in vari­ous ca­pa­cit­ies, in­clud­ing terms on the Board of Trust­ees and the Coun­cil. This long as­so­ci­ation with the AMS played a part in her de­cision, in cel­eb­ra­tion of her 90th birth­day last year, to make a ma­jor dona­tion to the So­ci­ety. The gift from her and her hus­band, Her­bert Mor­awetz, sig­ni­fic­antly in­creased the size of the long-un­der-fun­ded Os­wald Veblen Prize Fund, bring­ing it on a par with oth­er AMS prize funds.

Veblen was a good friend of Mor­awetz’s fath­er, John Lighton Synge. How this friend­ship began is re­coun­ted in Synge’s art­icle “For the 100th birth­day of the Amer­ic­an Math­em­at­ic­al So­ci­ety”, which ap­peared in A Cen­tury of Math­em­at­ics in Amer­ica: Part 1, ed­ited by Peter Duren (AMS, 1988). The art­icle is a writ­ten ver­sion of a talk Synge gave at the AMS Centen­ni­al Cel­eb­ra­tion in 1988. In the art­icle, he re­calls an AMS meet­ing he at­ten­ded in Decem­ber 1921 in Toronto. He had come to Toronto from Dub­lin the year be­fore and found few col­leagues with math­em­at­ic­al in­terests sim­il­ar to his own. His en­counter with Veblen at that AMS meet­ing and the kind­ness and con­sid­er­a­tion Veblen showed were im­port­ant to Synge as he made his way in math­em­at­ics in a new land.

At the time Synge wrote the art­icle, he was 91 years old, the same age his daugh­ter is now. One hears in his art­icle an echo of the lively in­tel­lect and warmth of Cath­leen Synge Mor­awetz. For those qual­it­ies and for her many con­tri­bu­tions to math­em­at­ics and to the pro­fes­sion, she has evoked great fond­ness in the math­em­at­ic­al com­munity. Happy 91st, Cath­leen