David Harel's advice to the young theoretical computer scientist

As second installment of the series in which Fellows of the EATCS provide their advice to the budding TCS researcher, I am posting the advice from David Harel. Enjoy!

Advice I would give to a student interested in TCS:

If you are already enrolled in a computer science program, then unless you feel you are of absolutely stellar theoretical quality and the real world and its problems do not attract you at all, I’d recommend that you spend at least 2/3 of your course efforts on a variety of topics related to TCS but not “theory for the sake of theory”. Take lots of courses on languages, verification AI, databases, systems, hardware, etc. But clearly don’t shy away from pure mathematics. Being well-versed in a variety of topics in mathematics can only do you good in the future. If you are still able to choose a study program, go for a combination: TCS combined with software and systems engineering, for example, or bioinformatics/systems biology. I feel that computer science (not just programing, but the deep underlying ideas of CS and systems) will play a role in the science of the 21^st century (which will be the century of the life sciences) similar to that played by mathematics in the science of the 20^th century (which was the century of the physical sciences).

Advice I would give a young researcher in TCS:

Much of the above is relevant to young researchers too. Here I would add the following two things. First, if you are doing pure theory, then spend at least 1/3 of your time on problems that are simpler than the real hard one you are trying to solve. You might indeed succeed in settling the P=NP? problem, or the question of whether PTIME on general finite structures is r.e., but you might not. Nevertheless, in the latter case you’ll at least have all kinds of excellent, if less spectacular, results under your belt. Second, if you are doing research that is expected to be of some practical value, go talk to the actual people “out there”: engineers, programmers, system designers, etc. Consult for them, or just sit with them and see their problems first-hand. There is nothing better for good theoretical or conceptual research that may have practical value than dirtying your hands in the trenches.

A short description of a research topic that excites me at this moment in time (and possibly why):

I haven’t done any pure TCS for 25 years, although in work my group and I do on languages and software engineering there is quite a bit of theory too, as is the case in our work on biological modeling. However, for many years, I’ve had a small but nagging itch for trying to make progress on the problem of artificial olfaction ̶ the ability to record and remotely produce faithful renditions of arbitrary odors. This is still a far-from-solved issue, and is the holy grail of the world of olfaction. Addressing it involves chemistry, biology, psychophysics, engineering, mathematics and algorithmics (and is a great topic for young TCS researchers!). More recently, I’ve been thinking about the question of how to test the validity of a candidate olfactory reproduction system, so that we have an agreed-upon criterion of success for when such systems are developed. It is a kind of common-sense question, but one that appears to be very interesting, and not unlike Turing’s 1950 quest for testing AI, even though such systems were nowhere in sight at the time. In the present case, trying to compare testing artificial olfaction to testing the viability of sight and sound reproduction will not work, for many reasons. After struggling with this for quite a while, I now have a proposal for such a test, which is under review.