Poul
Heegaard (1871 - 1948),
a home page, created by Ellen S. and Hans J. Munkholm.
Poul Heegaard was a professor of mathematics at Copenhagen University 1910
- 1917 and at Christiania (later Oslo) University 1918 - 1941. Today
he is best known for his contributions to the study of three-manifolds;
in fact Heegaard
splittings and Heegaard diagrams are household words in that area,
unfortunately often with the name misspelled as Heegard or even Hegard.
In addition, many topologists will know that Heegaard
gave a counter example to Poincaré's
first formulation of his duality theorem, and that Heegaard and Dehn's
article Analysis Situs (1907, in the Enz. der Math. Wissenschaften) marks
the foundation of combinatorial topology.
En biografisk artikel, Poul Heegaard (1871 - 1948), dansk - norsk
topolog, af Ellen S. Munkholm og Hans J. Munkholm, findes
her i .html format. Den er næsten identisk med en
artikel med samme titel, som er udkommet i NORMAT i 1998. Den har et noget
andet sigte end den nedenfor omtalte engelsksprogede artikel.
A biographical article, Poul Heegaard,
by Ellen S. Munkholm and Hans J. Munkholm appears in a volume on
the history
of topology, edited by Professor Ioan James for Elsevier. The .html
file of a preprint (with links to most of the illustrations)
is available. So is the .dvi
file (less the illustrations). Five of the six
illustrations from the preprint, as well as two auxiliary pictures, can
be found here:
Figure
1 (from preprint). Picture from the obituary, by permission from the Norwegian
Academy of Science and Letters.
Figure2
(from preprint). The first half page of Heegaard's
Autobiographical Notes.
Figure 3 (from preprint). Poul Heegaard at his prime (unknown date). Original
belongs to Lars and Rese Hjelle.
Figure 5 (from preprint). This photo of Poul Heegaard, and his father,
Sophus Heegaard, was taken shortly after the death of Poul Heegaard's older
sister, Henny. Original belongs to Lars and Rese Hjelle.
Figure 6 (from preprint) Poul Heegaard ("Bobo") as remembered by his granddaughter,
Rese Hjelle. Original belongs to Lars and Rese Hjelle.
In 1917, the Danish tabloid Ekstrabladet had several articles about a feud
between Harald Bohr and Poul Heegaard. This picture shows the text of one
of these articles (in Danish) and an accompanying cartoon of
Harald
Bohr who was a soccer player of a national reputation.
This shows the front page of a periodical that was published in Oslo 1941
- 45. In vol. 4, issue 2, one finds an article by Poul Heegaard on his
genealogical interests.
In preparation for the article Poul
Heegaard, the authors searched the Internet for relatives of Poul
Heegaard. One of the relatives found this way, Poul E. Heegaard, Trondheim,
turned out to have in his possession roughly 130 pages of handwritten notes
that were written (in Norwegian) by Poul Heegaard in 1945 and intended
as a family history for Heegaard's children and grandchildren. The above
link takes you to a transcript (in Danish) of the notes.
Heegaard's radio causeries
In 1944 - 45, Heegaard gave a series of radio causeries on Naturvitenskabens
høvdinger (The Chiefs of Natural Science) in the Norwegian Radio
NRK.
The manuscripts for this series have been preserved by Poul Heegaard's
granddaughter, Rese Hjelle. To appreciate the effect of such a series on
the contemporary Norwegian Society, one may take a look at two excerpts
from Hans Frederik Dahl: Dette er London, NRK i krig 1940 - 45.
On p.
309, one finds a government order from 1941 to hand in to the local
authorities all privately owned radio sets. For the rest of the occupation
period, radios were allowed only in those households which had a paid subscription
to the official paper Fritt Folk and where a majority of the people were
members of the Nazi party. The second excerpt, from p.
315, records the official number of NRK listeners in 1944 as 13,902,
just around 2 % of the prewar figure of 650,000.
A list of the scientists portrayed in the series is on p. 2 of Heegaards
radioforedrag i NRK, 1944 - 45 (in Danish).
The introductory paragraphs of the manuscripts concerning daVinci
and Kant
are available. On the back of the latter manuscript, Heegaard had penciled
a brief submission note to the Norwgian radio, signed with the official
Nazi signature Heil
og sæl.
Heegaard and knot theory
Heegaard's work on three-manifolds, mentioned above, led him to a study
of knots. This aspect
of his work has been studied by Jozef
Przytycki in a
preprint from IMADA, Odense University.
In connection with this work, Agata
Przybyszewska translated a part
of Heegaard's dissertation into English.
In 1947, Heegaard revised the manuscripts for the above mentioned radio
causeries to form the backbone of a manuscript (in Danish) ``Great Men
of Natural Science until the Eighteenth Century''. The above link takes
you to a transcript of the manuscript. In it, Heegaard has reproduced a
drawing, made by one of his students, showing Pythagoras
before
and after his main discovery.
Travelling in Finmarken
In March and April of 1920 Poul Heegaard went on a long trip to the Northernmost
parts of Norway to give popular lectures on astronomy in several places,
including the town of Kautokeino
. He has described this experience in a series of letters (in Danish) to
his friend, High School Principal Karl Hude, Hillerød, Denmark.
The letters were published as an irregular serial entitled ``Paa Reise
til Finmarken'' by the local newspaper Frederiksborg Amts Avis during the
months of May and June 1920. We have not found the date of the first letter;
the last one appears in the newspaper on June 19, 1920. In the
autobiographical notes, Heegaard mentions the tour in section 19.9,
and an anecdote from there is included in the above mentioned preprint.
Hans J. Munkholm <hjm@imada.sdu.dk>
