Ernest Jean Philippe Fauque de Jonquières

Ernest de Jonquières entered École Navale at Brest in 1835. After graduating he spent 36 years in the French navy. He was appointed vice-admiral in 1879, retiring in 1885. He travelled throughout the world with the navy but he spent substantial period in Indochina.

He became interested in mathematical research after reading the works of Poncelet and Chasles. After this introduction to advanced mathematics it is not surprising that his main interests were geometry. He made many contributions extending the work of Poncelet and Chasles.

In 1859 Jonquières the birational transformation, later studied by Cremona, which are

x x,   y [a(x) y + b(x)]/[c(x) y + d(x)] where a(x) d(x) - b(x) c(x) 0.

In 1862 he was awarded two-thirds of the Grand Prize of the Paris Academy for his work on fourth order plane curves. He also studied curve beams and algebraic curves and surfaces linking his work with that of Salmon, Cayley and Cremona.

In addition Jonquières discovered results in the area of Schubert's Abzählende Geometrie (Enumerative geometry). He also worked on algebra and the theory of numbers.

L Novy and J Folta, writing in [1], state that:-

... his results form a series of detailed supplements to the work of others and reflect Jonquières's inventiveness in calculating rather than a more profound contribution to the advancement of the field.

The work [2] in the references is an autobiography.

Texto original por: J J O'Connor and E F Robertson

JOC/EFR December 1996	School of Mathematics and Statistics University of St Andrews, Scotland
The URL of this page is: http://www-history.mcs.st-andrews.ac.uk/history/Mathematicians/Jonquieres.htm