Saturday, May 19, 2018

Coming up for Air

Once again, I bit more than I could chew. I thought I could organize, or help organize, three workshops as part of FLoC 2018 (Women in Logic, Natural Language in Computer Science and Linearity/LTTA) and I have spent the last six weeks, drowning in overdue papers, overdue reviews, overdue comments, overdue any kind of stuff. So much so that I haven't be able to even sit in the garden or watch stupid television for a while. What's the point of living in sunny California if you can't even sit in the garden, one may ask...

But today I think things might be getting better, touch wood. Still lots of to-dos undone, but  papers have been chosen, workshops are going ahead, they have preliminary programs, authors have been told. There might be a lull on the incessant pounding of "being late". So maybe one can sit on the garden, with a lemonade and try to think through the rest of what needs doing. After all the point of being a researcher is presumably researching stuff that you find interesting, not doing bureaucratic stuff non-stop. Maybe I can ponder one or two or ten conversations that were left hanging in the middle. One or two urgent emails that are now so old  that it will be surprising if they still matter. Worth a go, anyways.

Friday, May 4, 2018

Surely you're joking, Mr Martin-Löf?...

Many, many years ago, when I was a young postdoc I gave a talk in Uppsala about Dialectica categories and Full Intuitionistic Linear Logic. I was pretty pleased with how the mathematics of my thesis had panned out and when question time came and I had a question from a distinguished Swedish professor, I thought I was on safe grounds. He asked "ok, this is all very well, the categorical constructions are nice, I can see why you might want to consider a more intuitionisitic version of a multiplicative disjunction, but...what does it all mean? How do you tell a man in the street what you do?" And yes, the distinguished professor whom I had not met till then, was prof Per Martin-Löf (second from the right in the picture above) and it took me several years to get at least preliminary answers to his (very reasonable we all agree) questions.

Now the question is in Twitter, pestering me again, and I still do not have a proper answer. But I have a suggestion, given to me by Luiz Carlos Pereira, a good friend and collaborator. (It took me more than 3 hours ransacking my old notebooks to find it, so I feel that I should write it down, as well as I can, in this week of drowning-by-reviews...)

Now, everyone knows and some of us do enjoy shopping. The earlier Linear Logic examples were all about Camels and Malborough packets. Some people decided to change them to chocolate and coffee, but the vending machines stayed. Now in this era of Amazon and Walmart, let us describe a "FashionMall Semantics". (In Rio, "fashion mall" is not a common noun compound, but a proper noun. It's a sophisticated shopping center in one of the most unequal, on your face, terrible, parts of town, where the `favela'  and the uber-consumption face each other, in threatening ways. still...)
Anyways the FashionMall in Sao Conrado has all kinds of stores you might want to buy nice things from. So if the mall issued tickets for shopping, you could think of these tickets as ways of satisfying consumers' orders:

  •  If the mall gave you a ticket marked A\otimes B, then the mall has to have both A and B in stock and when you use your ticket, you  take both A and B  home.
  • If the mall gave you a ticket marked A&B, their stock has to have both, but you, the customer, can only take one of them home. You can choose which one A or B  you take home.
  • If the mall gave you a ticket marked A\oplus B, the stock only has to have one of A or B and the seller will choose which one it will give you. 

So far so good and similar to other explanations of Linear Logic using commercial transactions. But what can we say about A\par B?  Well, if the mall gives you a ticket marked A\par B they must have both in their stock,  you, the customer can only take one home, but you can take it back to the mall and swap it for the other one, if you want to do it. (The par operator is commutative, in the way that linear implication is not...)You do have to keep one of the two (A or B), though.

So more interesting still, if the mall gave you a ticket marked A\lollipop B what can we say?  Then we have a complicated transaction: if the buying of the antecedent  A is satisfied, then the buying of the consequent B has to be satisfied, whatever these buyings may be.  (some might use  "higher-order rule" to describe this transaction, but this  is somewhat familiar from  BHK-style interpretations.) Following this line of reasoning, a transaction A\lollipop \bot could be a transaction that cannot be satisfied.

And the units of Linear Logic, what happens to them? Well some "buys" cannot be satisfied, because the mall does not have the required stock. Other buys cannot be satisfied independently of the stock, just relating to what the costumer and the seller want to do.

There is much more that we need to work out to make  sure these intuitive notions  agree with the mathematics of Full Intuitionistic Linear Logic, but I hope this is enough to start the conversation. (and it gives me the chance to post a picture of friends Per, Steve and Richard, as well as the late Vladimir Voevodsky whom I had never had the pleasure of meeting: he really seemed a nice guy.)

Tuesday, October 10, 2017

Ada Lovelace Day 2017


It is sad that my Ada Lovelace post this year has to be for Maryam  Mirzakhani. I never knew she was ill and had hoped to catch some impressive-named lectures from her in Stanford, sooner or later. I thought I had plenty of time. And Stanford has some pretty amazing lecture series asking for general audience kinds of talks. The woman was really impressive, it is a real shame to see her gone so young.

And yes this has been such a bad year for mathematicians, it feels spooky. Fred Linton  and Vladimir Voevodsky (I need to read the long thread in the Coq mailing list) in September and Miles Tierney in October.  But, personally for me, the hardest, Mike Gordon in  August. So very sad!


Monday, September 25, 2017

Meaning in Context?


So this was already the third meeting on Meaning in Context, but I finally got to hear about it.
Annie sent an invitation to Meaning in Context (MIC 3)
and I choose to join the working group on
Neural networks and Textual Inference, animated by Lauri Karttunen and Ignacio Cases.
 
What I did not understand was that I supposed to come to all the other talks too. Or maybe I wasn't. But the two days that I went  there were really very informative. Learned lots, as usual. 
 
The previous Meaning in Context were in Dagstuhl (edited by Hans Kamp, Alessandro Lenci and James Pustejovsky) and Munich (edited by Hinrich Schutze).
 
I finally met Ido Dagan and Jason Baldridge, which was nice. Now I need to see whether and if so,  how, can we move the work with  Livy and Katerina in such way as to use some of the ideas I hope we can borrow.

Friday, July 14, 2017

Logic at LiCS2017



































Since there are no pictures of me talking at the Logic Mentoring Workshop (LMW) the mural at Keflavik Airport in Iceland will have to do.

I talked about "Weapons of Math Construction" (slides) and was pleased that after a certain amount of to-and-froing with the organizers, we were all happy with the event.

Also very happy with the quality of the talks in the "Women in Logic Workshop (WiL2017).

Not so happy with the discussion in the LiCS Business Meeting. As the SIGLOG chair Prakash Panangaden says in the SIGLOG news:

"At LICS in Reykjavik, Valeria de Paiva made a passionate plea for greater diversity in the LICS community. I think it is fair to say that not everyone was sympathetic. I don’t have the answers but certainly this issue cannot be ignored; it should be discussed widely.
I think it would be a great idea if people were to write to me or to the Editor so we can publish some of the opinions in the following two or three issues". 

I'm agreeing heartily with Prakash, everyone should write to him!

Thursday, July 13, 2017

Seven Different Valerias?





In some countries the legend is that cats have nine lives, in others  only seven.
Apparently Microsoft Academic (new version 2.0 just out!) thinks I am a cat.
At least there are seven Valerias de Paiva, when I search and they are all ME.

Check it out!
https://academic.microsoft.com/#/search?iq=%40Valeria%20de%20Paiva%40&q=Valeria%20de%20Paiva&filters=&from=0&sort=0
One of them has a paper with 144 other authors on Universal Dependencies, really cool.
https://academic.microsoft.com/#/detail/2229177960.

Thursday, June 15, 2017

Missing My Mentors

Oscar Wilde famously said: "To lose one parent may be regarded as a misfortune; to lose both looks like carelessness."

I wonder if the same applies to career mentors.


On the 5th June, I went to two memorial events, one at Stanford for Solomon Feferman, who died last year and another  one for Danny Bobrow who was my mentor and collaborator at Xerox PARC for almost nine years. Danny died on 20th March 2017. It hurts. It does get you down.

Also missing Grisha Mints!