# Looking for an electronic copy of Holmgren's old paper

I would like to know if anyone has an electronic copy of the following paper:

"Holmgren, E.: Über Systeme von linearen partiellen Differentialgleichungen. Översigt Vetensk. Akad. Handlingar 58, 91–105 (1901)"

In my search, the best result I found was the (possible) statement of the main result of this article which can be found in the following article: https://people.kth.se/~haakanh/publications/Hed-MZ2.pdf. More precisely,

Theorem (Holmgren) Suppose $$I$$ is a real-analytic nontrivial arc of $$\partial \Omega$$. Then if $$u$$ is smooth on a planar neighbohood $$\mathcal{O}$$ of $$I$$ and $$\Delta^N u=0$$ holds on $$\mathcal{O} \cap \Omega$$ with $$\partial_{n}^{j-1}|_I=0$$ for $$j=1, \dots, 2N$$, then $$u(z)=0$$ on $$\mathcal{O} \cap \Omega$$, provided that the open set $$\mathcal{O} \cap \Omega$$ is connected.

• The article has a zbMath entry, with a short abstract. This article by Hörmander also gives an overview. As a curious coincidence my grandfather Benny Brodda (who studied for some time under Hörmander) gave an extension to this theorem (using a generalisation due to F. John), see this article. I have not been able to find a copy of Holmgren's article yet. Aug 17, 2021 at 21:23
• In the meantime, in Hörmander's book "Linear partial differential operators" (1963), Chapter V, §5.3 (page 123), you'll find a full proof of Holmgren's theorem. It is formulated differently from your reference, but the content of the theorem is the same. I can post this formulation as an answer, if you wish. Aug 17, 2021 at 21:32
• Thank you! I know this version of Holmgren's Theorem, as in Hörmander's book. I was looking for the original article more out of curiosity, I didn't even find Holmgren's profile on MathSciNet, just some papers published in the Mathematische Annalen.
– Math
Aug 17, 2021 at 21:40
– Math
Aug 17, 2021 at 21:41