▁to ▁work ▁with ▁Vil helm ▁B jer kn es , ▁under ▁whose ▁influence ▁she ▁became ▁interested ▁in ▁the ▁mathematics ▁of ▁waves ▁and ▁the ▁work ▁of ▁Tul lio ▁Le vi - C iv ita ▁in ▁this ▁subject . ▁She ▁returned ▁to ▁Paris ▁in ▁ 1 9 3 0 , ▁married ▁another ▁math ematic ian , ▁Paul ▁D ubre il , ▁and ▁joined ▁him ▁on ▁another ▁tour ▁of ▁the ▁mathematics ▁cent ers ▁of ▁Germany ▁and ▁Italy , ▁including ▁a ▁visit ▁with ▁Le vi - C iv ita . ▁The ▁D ubre ils ▁returned ▁to ▁France ▁again ▁in ▁ 1 9 3 1 . ▁ ▁Career ▁and ▁research ▁ ▁While ▁her ▁husband ▁taught ▁at ▁L ille , ▁D ubre il - Jac ot in ▁continued ▁her ▁research , ▁finishing ▁a ▁doctor ate ▁in ▁ 1 9 3 4 ▁concerning ▁the ▁existence ▁of ▁infinitely ▁many ▁different ▁waves ▁in ▁ideal ▁liqu ids , ▁under ▁the ▁super vision ▁of ▁Henri ▁Vill at . ▁Before ▁her , ▁the ▁only ▁women ▁to ▁obtain ▁doctor ates ▁in ▁mathematics ▁in ▁France ▁were ▁Marie ▁Char pent ier ▁in ▁ 1 9 3 1 ▁( also ▁in ▁pure ▁mathematics ) ▁and ▁Ed m ée ▁Ch andon ▁in ▁ 1 9 3 0 ▁( in ▁astronom y ▁and ▁ge odes y ). ▁ ▁Following ▁her ▁husband , ▁she ▁moved ▁to ▁Nancy , ▁but ▁was ▁unable ▁to ▁obtain ▁a ▁fac ulty ▁position ▁there ▁herself ▁because ▁that ▁was ▁viewed ▁as ▁ne pot ism ; ▁instead , ▁she ▁became ▁a ▁research ▁assistant ▁at ▁the ▁University ▁of ▁R ennes .