A lot of mathematical knowledge has been formalized and stored in
repositories by now: different mathematical theorems and theories have been
taken into consideration and included in mathematical repositories.
Applications more distant from pure mathematics, however --- though based on
these theories --- often need more detailed knowledge about the underlying
theories. In this paper we present an example Mizar formalization from the area
of electrical engineering focusing on stability theory which is based on
complex analysis. We discuss what kind of special knowledge is necessary here
and which amount of this knowledge is included in existing repositories.Comment: To appear in The 9th International Conference on Mathematical
Knowledge Management: MKM 201