Person: Jensen, Johan Ludwig
Johan Ludwig Jensen was a Danish mathematician and engineer who worked on the Riemann hypothsis and convex functions.
Mathematical Profile (Excerpt):
 Jensen was essentially self taught in research level mathematics and never held an academic appointment.
 The Company thrived, at least in part through the high level of technical skill that Jensen possessed.
 For his whole working life Jensen was an amateur mathematician only doing mathematics in his spare time.
 Jensen contributed to the Riemann Hypothesis, proving a theorem which he sent to MittagLeffler who published it in 1899.
 The theorem is important, but does not lead to a solution of the Riemann Hypothesis as Jensen had hoped.
 In a paper which he published in Acta mathematica in 1906, Jensen proved an inequality for convex functions which had a whole host of classical inequalities as special cases.
Born 8 May 1859, Nakskov, Denmark. Died 5 March 1925, Copenhagen, Denmark.
View full biography at MacTutor
Tags relevant for this person:
Origin Denmark, Number Theory
Thank you to the contributors under CC BYSA 4.0!
 Github:

 nonGithub:
 @JJO'Connor
 @EFRobertson
References
Adapted from other CC BYSA 4.0 Sources:
 Oâ€™Connor, John J; Robertson, Edmund F: MacTutor History of Mathematics Archive