An important mathematical event occurred while he was at Göttingen, for that was the year in which Holmgren lectured on Fredholm 's theory of integral equations at Göttingen. Hilbert immediately saw the he importance of Fredholm 's theory and work at Göttingen on this topic began immediately. Plemelj was a major contributor to this work and he was among the first to make major advances.
Isang mahalagang matematiko kaganapan ang naganap habang siya ay sa Gottingen, para sa na ay ang taon kung saan Holmgren lectured sa Fredholm 's theory ng integral equation sa Gottingen. Hilbert agad-agad na nakita niya ang kahalagahan ng Fredholm 's theory at trabaho sa Gottingen sa paksang ito ay nagsimulang kaagad. Plemelj ay isang pangunahing kontribyutor sa trabaho na ito at siya ay kabilang sa mga unang na gumawa ng mga malalaking pagsulong.