追憶陳載澧博士

A tribute to my teacher

As an undergraduate student in HKU, I have heard of Dr Chan's name almost as early as I entered university, as I regularly received mails from the General Education Unit (yes, at that time the information was mailed to students' homes), in which details on the general education courses were covered by a letter signed by Dr Chan, the then Director of General Education. I still remember that I learnt the phrase "exams are necessary evils" there, and that Dr Chan kept emphasising that the general education courses were meant to let students broaden their horizons in the absence of exam pressures.

At that time I did not know that Dr Chan was a member of the Department of Mathematics. Materials from the General Education Unit were in Chinese, and so was Dr Chan's name on the letter. On the other hand teachers' names on the website of the Department Mathematics were in English (with given names in initials, i.e. C.L. Chan in this case), so I had not been able to match the two names until much later.

I did not really get to know Dr Chan personally until the last semester before his retirement, when I took the course Probability Theory which he was to teach for the last time. He told us in the first class that "I have been teaching this course on and off for more than twenty years". Like many other teachers in those days, he had everything in his mind so he could keep writing on the board and explaining to students without any reference materials in hand.

One day I and some other classmates talked to Dr Chan after class. At the end of the conversation Dr Chan said "let's go for coffee together next time", and we agreed. Then at the end of the next class as Dr Chan was about to leave the classroom we nervously discussed whether we should take the initiative to honour the agreement!

The final exam of the Probability Theory course in that semester (probably the last "necessary evil" created by Dr Chan) also left me with deep impression. In a class towards the end of the semester, Dr Chan said he was repeatedly urged by the Department to submit the exam paper which had been overdue for a long time. Then on the day of the exam we were handed two surprises with the exam paper. The first surprise was that the 4 pages of exam paper were printed on one sheet of A3-sized paper with the characteristic marks of photocopying machines. Probably the papers were printed by the Department as it was too late for the then Exam Unit (today's Exam Office) to print, where in the latter case the exam papers would always be printed on A4-sized paper (and without marks of photocopying machines) even if the number of pages is 3 or 4. I've still been keeping that A3-sized hard copy in my office.

The second surprise is with the content of the exam paper. In those days the "HKU Exambase" had been set up by the library, so we were able to see the past exam papers. In preparing for an exam we would typically work on some recent past exam papers for practice. The past exams of the course Probability Theory looked relatively standard, with similar questions appearing in the previous exam papers. But not for the very last one by Dr Chan. I still remember that when the exam started, Dr Chan kind of announced (in Cantonese): "...this exam paper may look unfamiliar (in Cantonese: 生口生面) to you, but bear in mind that it is not hard..." I pretty much enjoyed working on those "unfamiliar questions". Before the very last part (Question 3(b)(ii)) of the question paper there was a remark, which was rarely seen in exams I have taken in HKU: "The following computations are considerably more complicated than those in (i). Try it if you have time. Proceed systematically and go as far as you can." I did try to go as far as I could, but I did not have sufficient time to complete everything.

I knew that Dr Chan started a new endeavour in HKBU after his retirement from HKU. Later when I taught at HKBU I had some interactions with colleagues from the Centre for Holistic Teaching and Learning (CHTL) there, although by that time Dr Chan had already retired from the post of CHTL Director. After returning to my alma mater I had the chance to meet Dr Chan again in a departmental outing, albeit for the last time.

While Dr Chan has left us, what we have learned from him, both within and beyond the subject of mathematics, will remain in our heart. May Dr Chan rest in peace.

LAW Ka Ho
18th October 2021

(Original article and photo were posted on the website of Department of Mathematics, HKU:
https://hkumath.hku.hk/web/memory/memory_clchan_main.php)