Thursday, June 10, 2021

The Future of Faculty Hiring

Faculty hiring in computer science is a process long due for an overhaul. The pandemic certainly changed some of the dynamics moving most of the interviews online and saving a ton of money and time. Will this be the start of a fresh approach to recruiting?

A typical search in the past few years had some schools flying in 30-40 candidates, typically costing over a $1000 each and a full-time job for a staff member during the search. We'd justify the expense as small compared to the millions we'd invest in a faculty member throughout their career, but it is generally the largest discretionary expense for a CS department. It also gives advantages to rich departments over others.

During the pandemic all those interviews moved online and worked reasonably well at virtually no additional cost. Also no need to scrounge around to find faculty willing to skip family meals to have dinner with the candidates. And if a faculty had a conflict with a candidate on the interview day, they could schedule on a different day. There really is no reason to have all the meetings on the same day.

With the pandemic mostly behind us, will we go back to in-person interviews moving forward. I suspect the airport interview, where you fly out 20 or so candidates to have hour long interviews in a hotel near an airport with a search committee for an administrative position, will be the first to go completely virtual. 

Even for regular faculty interviews, there will be great pressure to reduce the number of in-person visits, perhaps to just the top candidates, or just the ones who have offers--make the "second visit" the only visit. Richer departments may find the expense worthwhile to make a bigger impression on the candidates and that will only expand the advantage of wealthier universities.

Times like this are the perfect opportunity for CS leadership to come in and give some sanity to the hiring process but I'm not holding my breath.

Sunday, June 06, 2021

When do you use et al. as opposed to listing out the authors? First names? Middle initials? Jr?

 If I was refering to the paper with bibtex entry: 


  author    = {Jeffrey Bosboom and

               Spencer Congero and

               Erik D. Demaine and

               Martin L. Demaine and

               Jayson Lynch},

  title     = {Losing at Checkers is Hard},

  year      = {2018},

  note      = {\newline\url{}},


(The paper is here.)

I would write 

Bosboom et al.~\cite{BCDDL-2018} proved that trying to lose at checkers (perhaps you are playing a child and want to keep up their self-esteem, or a Wookie and don't want your arms to be torn off your shoulders   (see here),  or a Wookie child) is hard. 

Why did I use et al. ? Because it would be a pain to write out all of those names. 

How many names does it take to make you write et al. ? Are there exceptions? 

I have not seen any discussion of this point on the web. So here are my rules of thumb and some questions.(CORRECTION- a commenter points out that this IS discussed on the web. Even so, you can comment on my thoughts or give your thoughts or whatever you like.) 

1) If  there are 3 or more people than use et al. Exception: If the three are VERY WELL KNOWN as a triple. E.g., the double play was Tinker to Evers to Chance. Well, that would not really come up since in baseball nobody ever says the double play was Tinker et al.  More relevant examples:

Aho, Hopcroft, and Ullman

Cormen, Leiserson, and Rivest, also known as CLR

The more recent edition is

Cormen, Leiserson, Rivest, and Stein. I have heard CLRS but I don't know if people WRITE all four names. 

Lenstra-Lenstra-Lovasz also usually mentions all three. 

2) If there is one name do not use et al.  unless that one person has a multiple personality disorder.

3) If there are 2 people it can be tricky and perhaps unfair. If the second one has a long name then I am tempted to use et al. For example

Lewis and Papadimitriou (If I mispelled Christos's name-- well- that's  the point!- to avoid spelling errors I want to use et al. )

Lampropoulos and Paraskevopoulou (the first one is UMCP new faculty!). After typing in the first name I would not be in the mood to type in the second. 

Similar if there are lots of accents in the name making it hard to type in LaTeX (though I have macros for some people like Erdos who come up a lot) then I might use et al. 

(ADDED LATER- some of the commenters object to my `rule' of leaving out the last name if its complicated. That is not really my rule- the point of this post was to get a discussion going about the issue, which I am happy to say has happened.) 


There are other issues along these lines: when to include the first name (when there is more than one person with that last name, e.g. Ryan Williams and Virginia  Vassilevska Williams), when to use middle initials (in the rare case where there is someone with the same first and last name- Michael  J. Fox added the J and uses it since there was an actor named Michael Fox.)

I will soon give a quote from a math paper that amused me, but first some context.  The problem of determining if a poly in n variables over Z has an integer solution is called E(n). By the solution to Hilbert's 10th problem we know that there exists n such that E(n) is undecidable. E(9) is undecidable, but the status of E(8) is unknown (as of May 2021) and has been since the early 1980's. 

Here is the quote (from here).

Can we replace 9 by a smaller number? It is believed so. In fact, A. Baker, Matiyasevich and J.Robinson  even conjectured that E(3) is undecidable over N.

Note that Baker and Robinson get their first initial but Matiyasevich does not.

I suspect that they use J. Robinson since there is another mathematician with last name Robinson: Rafael Robinson who was Julia's Robinson's husband (to my younger readers--- there was a time when a women who got married took her husband's last name). There is at least one other Math-Robinson: Robert W Robinson. I do not think he is closely related. 

Baker: I do not know of another mathematician named Baker. I tried Google, but the Bakers  I found were   not in the right time frame. I also kept finding hits to an anecdote about Poincare and a man whose profession was a baker (see here though its later in that blog post). However, I suspect there was another mathematician named Baker which is why the author uses the first initial.  Its possible the author did not want to confuse Alan  Baker with Theodore Baker, one of the authors of Baker-Gill-Solovay that showed there were oracles that made P = NP and others that made P NE NP.  But somehow, that just doesn't seem right to me. I suspect there is only one mathematician with last name Matijsavic. 

Thomas Alva Edison named his son Thomas Alva Edison Jr.  This was a bad idea but not for reasons of authorship, see here.

Thursday, June 03, 2021

What happened to self-driving cars?

In 2014, I wrote a blog post about a fake company Elfdrive.

With a near record-setting investment announced last week, the self-driving car service Elfdrive is the hottest, most valuable technology start-up on the planet. It is also one of the most controversial.

The company, which has been the target of protests across Europe this week, has been accused of a reckless attitude toward safety, of price-gouging its customers, of putting existing cabbies out of work and of evading regulation. And it has been called trivial. In The New Yorker last year, George Packer huffed that Elfdrive typified Silicon Valley’s newfound focus on “solving all the problems of being 20 years old, with cash on hand.”

It is impossible to say whether Elfdrive is worth the $117 billion its investors believe it to be; like any start-up, it could fail. But for all its flaws, Elfdrive is anything but trivial. It could well transform transportation the way Amazon has altered shopping — by using slick, user-friendly software and mountains of data to completely reshape an existing market, ultimately making many modes of urban transportation cheaper, more flexible and more widely accessible to people across the income spectrum.

It was a spoof on Uber but now it looks more like Tesla, expect that Tesla's market value is over half a trillion, about six times larger than General Motors.

The post was really about self-driving cars which I thought at the time would be commonplace by 2020. We are mostly there but there are issues of silent communication between drivers or between a driver and a pedestrian on who goes first that's hard to duplicate for a self-driving car. There is the paradox that if we make a car that will always stop if someone runs in front of it, then some people will run in front of it.

There is also the man-bites-dog problem. Any person killed by a self-driving car will be a major news item while the person killed by a human-driven car while you've been reading this post will never be reported.

We'll get to self-driving cars eventually, it just won't be all at once. We're already have basically self-driving cars on highways and in many other roads as well. As the technology improves and people see that it's safe at some point people will say, "So why do we even need the steering wheel anymore?"

Sunday, May 30, 2021

What is a natural question? Who should decide?

(Thanks to Timothy Chow for inspiring this post.)

My survey on Hilbert's Tenth Problem(see  here) is about variants of the problem. One of them is as follows: 

For which degrees d and number-of-vars n, is Hilbert's tenth problem decidable? undecidable? unknown? 

 I wondered why there was not a website with this information. More generally, the problem didn't seem to be getting much attention. (My survey does report on the attention it has gotten.) 

I got several emails telling me it was the wrong question. I didn't quite know what they meant until Timothy Chow emailed me the following eloquent explanation:


One reason there isn't already a website of the type you envision is that from a number-theoretic (or decidability) point of view, parameterization by  degree and number of variables is not as natural as it might seem at first glance. The most fruitful lines of research have been geometric, and so geometric concepts such as smoothness, dimension, and genus are more natural than, say, degree. A nice survey by a number theorist is the book Rational Points on Varieties by Bjorn Poonen. Much of it is highly technical; however, reading the preface is very enlightening. Roughly speaking, the current state of the art is that there is really only one known way to prove that a system of Diophantine equations has no rational solution.



1) ALICE: Why are you looking for your keys under the lamppost instead of where you dropped them?

   BOB: The light is better here.

2) I can imagine the following conversation:

BILL: I want to know about what happens with degree 3, and number of variables 3.

MATHPERSON: That's the wrong question you moron. The real question is what happens for fixed length of cohomology subchains.

BILL: Why is that more natural?

MATHPERSON: Because that is what we can solve. And besides, I've had 10 papers on it.


1) They are working on really hard problems so it is natural to gravitate towards those that can be solved.

2) I suspect that the math that comes out of studying classes of equations based on smoothness, dimension, genus is more interesting than what comes out of degree and number of vars. Or at least it has been so far. 


Who gets to decide what problems are natural?

People outside the field (me in this case) are asking the kind of questions that a layperson would ask and there is some merit to that.

People inside the field KNOW STUFF and hence their opinion of what's interesting to study has some merit. But they can also mistake `I cannot solve X' for `X is not interesting'

Tuesday, May 25, 2021

Does the university matter?

As we come out of a pandemic with online teaching and research collaborations, how much do we actually need the university?

Theoretical research in computer science, math and elsewhere it hardly slowed down with everyone hunkered down at home, and when it did it was more because of supervising kids with their on-line learning than being away from the university. Collaborating with those around the world was basically the same as collaborating with your colleagues on campus.

Many courses, especially the larger ones, worked about as well on-line as they do in person.

The pandemic is accelerating changes already in place. Before say 1960, the fastest travel for the masses was on train and boats and fast communication limited to expensive phone calls. You needed strong colleagues, a strong library and a strong support staff to be a successful academic. Traveling to meet colleagues and attend conferences was a luxury that few could do often.

The 60's gave us air travel though it wasn't until the 90's that we could readily send academic papers electronically. It's really only recently that we have the infrastructure to allow high-quality teaching and research collaboration online.

Suppose universities now just disappeared. Professors would be free agents, supported by grants and tuition from students taking their on-line courses and consulting. Students would pick and choose courses from the best instructors, their "transcript" being recorded on a blockchain-like database. PhD students would be more of an apprenticeship, a low salary in exchange for personalized mentoring from a professor. 

For the experimental sciences, there would be a set of national labs that professors could join.

Startups would create apps to enable all these things, professors would just become yet another piece of the gig economy. Superstar academics can pull in large salaries, the rest would struggle to make a decent wage--not that different from actors and musicians. 

Don't worry, universities aren't going anywhere soon. Or are they?

Thursday, May 20, 2021

Emerging from the Pandemic

The City of Chicago yesterday agreed with the latest CDC guidelines that those of us fully vaccinated no longer have to wear masks in most settings. Lollapalooza, the big Chicago music festival, will be held in full capacity this summer. There are still some restrictions but barring any surprise setbacks should be mostly gone by the Fourth of July.

It's not appropriate to call the pandemic over. Too many countries are suffering and lack good access to vaccines or strong health care. But in most of the US vaccinations are readily available and it really feels like we are putting the pandemic in the past.

Variants that beat the vaccines could emerge. Vaccines could become ineffective over time. Too many still need to be vaccinated and too many don't want to do so. Typically problems start small and quickly get big by exponential growth but likely with enough warning if we need boosters or extra precautions. And all those who cut in line to get shots early are now my canaries for the effects wearing off.

What will this post-pandemic world look like? Continued virtual meetings from people who don't want to spend the 10-15 minutes to get across campus or to come to campus at all. A bigger move to casual dress, even in the corporate world. No more snow days. Changes in ways we won't expect. 

We all have our different attitudes but I'm ready to move on. Time to start the "after times".

Sunday, May 16, 2021

Why do countries and companies invest their own money (or is it?) in Quantum Computing (Non-Rhetorical)

 There have been some recent blog posts by Scott (see here) and Lance (see here)  about the hype for SHORT TERM APPLICATIONS of Quantum Computing, which they both object to. 

I have a question that has been touched on but I want to get it more out there.

PREAMBLE TO QUESTION:  The following scenarios, while distasteful, do make sense: 

a) A researcher on their grants exaggerates or even out-right lies about the applications of their work. 

b) A journalist in their articles exaggerates or even out-right lies about the applications of the science they are covering.

c) A company exaggerates or even out-right lies about the applications of their project to a venture capitalist or other kind of investor. 


Why does a company or country invest THEIR OWN MONEY into Quantum Computing which is unlikely to have a short term profit or benefit? Presumably they hire honest scientists to tell them the limits of the applications in the short term. 


1) QC might be able to do something cool and profitable, like factoring, or simulating physics quantum experiments or something else, in the short term. Quantum Crypto is already happening, and that's a close cousin of Quantum Computing. 

2) QC might be able to do something cool and profitable (like in (1)) in the long term, and both companies and countries think they will be around for a long time. (For a list of America's 10 oldest companies see here.) 

3) The company or country is in this for the long term, not for a practical project, but because they realize that doing GOOD SCIENCE is of a general benefit (this might make more sense for a country than a company). And funding Quantum Computing is great for science. 

4) Bait and Switch: The company claims they are doing Quantum to attract very smart people to work with them, and then have those smart people do something else.

5) (this is a variant of 1) While Quantum Computing may not have any short term applications, there will be classical applications INSPIRED by it (this has already happened, see here).

6) Some of these companies make money by applying for GRANTS to do QC, so its NOT their money. In fact, they are using QC to  GET money.

7) For a country its not the leaders money, its that Taxpayer's money- though that still leaves the question of why spend Taxpayer money on this and not on something else.

8) For a company its not their money- its Venture Capitalists  and others (though for a big company like Google I would think it IS their money). 

9) The scientists advising the company or country are giving them bad (or at least self-serving) advice so that those scientists can profit- and do good science. So this is a variant of (3) but without the company or country knowing it. 

10) In some countries and companies group-think sets in, so if the leader (who perhaps is not a scientist) thinks intuitively that QC is good, the scientists who work for them, who know better, choose to not speak up, or else they would lose their jobs...or worse. 

11) For countries this could be like going to the moon: Country A wants to beat Country B to the moon for bragging rights. Scientists get to do good research even if they don't care about bragging rights. 

12) (similar to 11 but for a company) If a company does great work on QC then it is good publicity for that company. 

13) Some variant of the greater fool theory. If so, will there be a bubble? A bail-out? 

Thursday, May 13, 2021

Cryptocurrency, Blockchains and NFTs

 I first wrote about bitcoin in this blog ten years ago after I gave a lecture in a cryptography class I taught at Northwestern. Two years later I had a follow-up post, noting the price moved from $3 to $1000 with a market cap of about $11 Billion. My brother who thought they were a scam back then has since become a cryptocurrency convert. The bitcoin market cap is now over a trillion dollars and other cryptocurrencies are not far behind. No longer can we view cryptocurrencies as simply a neat exercise in applied cryptography now that it has serious value.

The main uses of cryptocurrencies are for speculation or illegal activities, such as drug sales, ransoms, money laundering and tax evasion. Sure you can buy a Tesla with bitcoins but that's more of a gimmick. Cryptocurrency spending is simply too slow, expensive and volatile right now to replace other methods of electronic payment. 

Non-fungible tokens (NFTs) truly puzzle me. They are just a digital certificate of authentication. What could you do with them you couldn't do with docusign? Collectibles of publicly available digital goods is a fad already fading.

I'm not a fan of a fiat currency governed by strict rules not under governmental control. Bad things could happen. However thinking of cryptocurrencies and the blockchain technology that underlies them have brought up real needs for our digital world.

  • An easy way to pay online without significant fees, expenses or energy consumption.
  • An easy and cheap way to transfer money between different countries.
  • A distributed database to allow tracking of supply chains, credentials and financial transactions for example. I see less a need to make these databases decentralized.
  • A need, for some, to have a digital replacement for the anonymity of cash.
  • People need something to believe in once they have given up believing in religion and a functioning democracy. 
Don't change your investing habits based on anything I write in this post. Speculation and illegal activities are powerful forces. Or it could all collapse. Make your bets, or don't.

Note: Since I wrote this post yesterday, Elon Musk tweeted that Tesla will no longer accept bitcoins, and the bitcoin market cap has dropped below a trillion.