Ernst Leonard Lindelöf

{{Short description|Finnish mathematician (1870–1946)}}

{{Redirect|Lindelöf|the surname|Lindelöf (surname)}}

{{Infobox scientist

| name = Ernst Lindelöf

| image = Ernst-Lindelof.jpg

| image_size =

| caption =

| birth_date = 7 March 1870

| birth_place = Helsinki

| death_date = {{death-date and age|4 June 1946|7 March 1870}}

| death_place = Helsinki

| nationality = Finnish

| fields = Mathematics

| workplaces =

| alma_mater = University of Helsinki (PhD, 1893)

| thesis_title = Sur les systèmes complets et le calcul des invariants différentiels des groupes continus finis

| thesis_url = https://books.google.com/books/about/Sur_les_syst%C3%A8mes_complets_et_le_calcul.html?id=M4hHAQAAIAAJ&redir_esc=y

| thesis_year = 1893

| doctoral_advisor = Hjalmar Mellin

| academic_advisors =

| doctoral_students = Lars Ahlfors
Rolf Nevanlinna
Pekka Myrberg

| notable_students =

| known_for = Lindelöf hypothesis
Lindelöf's lemma
Lindelöf's theorem
Lindelöf space
Phragmén–Lindelöf principle
Picard–Lindelöf theorem

}}

Ernst Leonard Lindelöf ({{IPA|sv|ˈlɪ̂nːdɛˌløːv}}; 7 March 1870 – 4 June 1946) was a Finnish mathematician, who made contributions in real analysis, complex analysis and topology. Lindelöf spaces are named after him. He was the son of mathematician Lorenz Leonard Lindelöf and brother of the philologist {{ill|Uno Lorenz Lindelöf|fi|Uno Lindelöf|lt=Uno Lorenz Lindelöf}}.{{Cite web|url=http://375humanistia.helsinki.fi/en/uno-lindelof/a-philologist-and-an-anglicist|title=A philologist and an Anglicist - 375 Humanists|website=375humanistia.helsinki.fi}}

He was secretary of the Finnish Society of Science and Letters (societas scientiarum Fennica) in its centenary year, 1938. {{Cite journal|url=https://royalsocietypublishing.org/doi/10.1098/rsnr.1938.0011|title=Societas Scientiarum Fennica|date=October 31, 1938|journal=Notes and Records of the Royal Society of London|volume=1|issue=2|pages=60–62|via=CrossRef|doi=10.1098/rsnr.1938.0011}}