It is mentioned in the following article
https://cacm.acm.org/news/210107-in-memoriam-rudolf-kalman-19302016/fulltext
that (with attribution which I suspect is wrong)
He also worked with Yu-Chi Ho on the minimal realization problem, resulting in what came to be known as the Ho-Kálmán algorithm.
I know that Yu-Chi Ho did work with Kalman, but on Kalman-Ho-Narendra Theorem, for example, Reference for Kalman-Ho-Narendra Theorem
On the other hand, in http://www.ece.uah.edu/PDFs/news/RT-sprsum2002.pdf, we can find the following mentioned by the mathematician R. W. Bass,
During the years just before and after Kalman accepted a professorship at Stanford in 1964 he published algebraic results pertaining to realization theory, or modeling of linear input-output systems, which laid the groundwork for a stunning discovery by his graduate student B. L. Ho. I am referring to Ho's doctoral dissertation's main result, published in 1966 as a joint paper with Kalman, which I regard as the most profound theorem pertaining to the Systems Identification (ID) problem.
the said paper (that I can trace) is "Effective Construction of Linear State-Variable Models from Input/Output Functions".
I know that Yu-Chi Ho is also called Larry Ho (at least according to wiki), and is a big shot in control theory. But he apparently is not Kalman's student, nor did he graduate from Stanford. The most recent news about B.L.Ho is in this article http://www.sontaglab.org/FTPDIR/kalman_students_article_2010.pdf where only his name appeared.
I wonder who B.L. Ho is? (at least the full name) Am I right that he is not Yu-Chi Ho? Many thanks!
Yes, B.L. Ho is Bin-Lun Ho, my father. I only recently found out his association with Rudolf Kahman as I was looking over copies of his doctoral dissertation. He went on after his time at Stanford to work in the hard disk drive industry.