**Hubert Stanley Wall** was an American mathematician who worked in the field of continued fractions.

- Hubert began his education in his home town of Rockwell City, attending the High School there.
- At Cornell College, Wall studied a wide range of subjects, including languages, physics, chemistry and mathematics.
- Elmer Earl Moots (1882-1970) taught Engineering and Mathematics at Cornell College and he inspired Wall to study mathematics at university.
- Moots had a reputation for advising his best students to undertake graduate work at the University of Wisconsin, Madison, so it is not surprising that he gave this advice to Wall who indeed entered that University in 1924.
- At the University of Wisconsin Wall's thesis advisor was Edward Van Vleck and Wall was awarded his Ph.D. in 1927 for his thesis On the Padé Approximants Associated with the Continued Fraction and Series of Stieltjes.
- After submitting his thesis, Wall went to Germany and worked at Göttingen with David Hilbert for a few months before returning to the United States to take up a position at Northwestern University, Chicago, in the autumn of 1927.
- Wall spent the academic year 1938-39 at the Institute for Advanced Study at Princeton.
- As a result, Wall later wrote 'Creative Mathematics' very much in the modern spirit of differential equations in which existence, uniqueness, qualitative study, and numerical computation are emphasized over 'closed form' solutions.
- Wall worked closely with Hellinger at Northwestern; they published a paper together, and Wall continued to work in the area of what became known as the Hellinger integral.
- Wall's interaction with Hellinger led to them running an analysis seminar in which they adopted the method of teaching where students have to work out the proofs themselves given only brief hints.
- We note that, as we mentioned above, Wall had observed Van Vleck adopting this approach when reading papers.
- Wall explained his ideas on teaching in the Preface to Creative Mathematics (1963).
- In 1944 Wall left Northwestern University and spent two years at the Illinois Institute of Technology.
- when Wall came to The University of Texas, it was natural for him to utilize the seminar method of instruction even more fully, and this he did.
- What Wall did to the theory of continued fractions was to synthesize a large part of it.
- A third area in which Wall made a very substantial contribution was the characterization of Hausdorff Moments by means of continued fractions, and also some continued fraction transformations which enabled him to obtain inclusion relations for Hausdorff Summability Methods.
- We have referred to Wall's book Creative Mathematics several times above.
- Wall himself called this book "a sketchbook in which readers try their hands at mathematical discovery." That is a fair and accurate assessment.
- Wall was an invited principal speaker at the 'International Conference on Padé Approximants, Continued Fractions and Related Topics' held at the University of Colorado, Boulder, in June 1972.
- However, he died before the conference took place and the Proceeding of the conference were dedicated to Wall.
- These proceedings are dedicated to the late Professor H S Wall, whom we had hoped to have as a principal speaker when we first planned the conference.

Born 2 December 1902, Rockwell City, Calhoun County, Iowa, USA. Died 12 September 1971, Austin, Travis County, Texas, USA.

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Origin Usa

**O’Connor, John J; Robertson, Edmund F**: MacTutor History of Mathematics Archive