Learning from Penelope

 

In Homer’s Odyssey, Penelope survives not by force, but by craft.

She weaves by day and unweaves by night. The weaving keeps the suitors at bay; the unweaving buys her time. It is not indecision. It is strategy. It is control over her own narrative.

I have decided to learn from Penelope.

Over the next months (or years), I will be rewriting my old papers.

Not because the mathematics is wrong.
Not because the results no longer matter.
But because I was — and perhaps still am — a lousy communicator.

Many of my early papers were written quickly, defensively, or under constraints that now feel foreign: editorial fashions,  page limits, the pressure to “fit” a venue. Many were published behind paywalls that I cannot even access anymore, given the lack of institutional support. The irony is not lost on me: I cannot easily read my own work. And cannot point others to it.

Commercial publishing has made something strange happen in mathematics. We produce knowledge collectively, mostly publicly funded, then hand it over to companies who sell it back to us. The system has normalized the idea that authors do not own access to their own intellectual labor. That should trouble us more than it does.

But this project is not primarily about protest.

It is about clarity.

If I am serious about Network Mathematics, and about mathematics as a way of life — about extracting structure from the literature while also living responsibly within it — then my own work should not be an obstacle. It should not require insider knowledge to decode. It should not assume a reader who already knows what I mean to say. So I am weaving again.

I will rewrite old papers as arXiv preprints: With clearer motivations. With expanded explanations. With better examples. With connections made explicit. With historical context where I once assumed it was obvious. With diagrams where prose struggles. With prose where diagrams obscure.

Some papers may be gently revised. Some may be substantially reorganized.
Some may need to be undone and rewoven almost entirely.

This is not repudiation. It is evolution.

Mathematics deserves expository care. Ideas deserve to be legible beyond the circle that first conceived them. And younger researchers — including my younger self — deserve texts that do not require deciphering as a rite of passage.

Penelope’s weaving was an act of resistance. Mine is an act of responsibility.

If you have ever read one of my older papers and thought, “I suspect there’s something important here, but I wish it were clearer,” this project is for you. If you have ever struggled to access your own published work, this project is for you. If you believe that clarity is not a concession but a form of rigour, then perhaps this project is for all of us.

I am unweaving.

So that I can weave again.

Manels and their effects (on my health)

 Maybe you haven't heard about `Manels'? As Gemini explains: A "manel" is a panel of professionals, often at conferences or in media, composed entirely of men. It is often seen as a failure of diversity, equity, and inclusion (DEI), implying that women are either not qualified to contribute or that their perspectives are unnecessary.

 

One of the most widely cited and "outrageous" examples of a manel in the context of reproductive health occurred in 2017. A group of approximately 25 Republican men was photographed in the White House discussing a healthcare bill that included significant changes to pregnancy and maternity care, as well as the defunding of Planned Parenthood. The image became a viral symbol of the exclusion of women from the very policies that govern their bodies and lives, according to the BBC.

Yes, I know that one is not supposed to talk about DEI in the USA in 2026. Even the word "women" can get your research project proposal disqualified! Still, it took me a while to construct the email message below about manels in my kind of research and I want to be able to point people to it.

 

On all male programs and PCs (again)

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Dear colleagues,

I’m writing to raise—yet again—an issue that many of us encounter with dispiriting regularity: conferences, workshops, and events in logic whose visible leadership is overwhelmingly male—whether in the form of all-male (or nearly all-male) invited speaker lineups, all-male program committees, or both.

I want to be explicit about scope. I am not interested in debating whether particular cases are “small,” “technical,” or “too specialized.” That line of argument is a familiar slippery slope, and in practice it serves to normalize exclusion rather than to explain it. In logic, there is no shortage of qualified women across areas. When both the speaker list and the PC skew heavily male, that reflects choices made during organization.

All-male programs and PCs are not neutral. Together, they send a clear signal about who is seen as authoritative, who is entrusted with gatekeeping roles, and who is assumed to represent the field. These signals accumulate: they shape visibility, invitations, evaluation practices, and ultimately who feels that they belong.

Organizers sometimes respond that exclusions are unintentional. That may be true—but unintentional bias is still bias, and its effects are not softened by good intentions. Organizing an event involves two clear points of intervention where effort can make a real difference:

1. Who is invited to speak, and

2. Who is asked to serve on the program committee or equivalent decision-making body.

Both are acts of curation and judgment, and both come with responsibility.

I also want to stress that this conversation is specifically about our mailing list, women-in-logic. This list is not moderated, many of us do not have the time or energy to act as moderators. But that does not mean we have to accept, circulate, or normalize calls for papers or announcements that reproduce the same exclusionary patterns we see on generic mailing lists. Setting expectations about what is acceptable here matters.

I would like to encourage two simple norms:

1. That we call attention—politely but explicitly—when all-male or overwhelmingly male speaker lineups or PCs are announced or promoted in our community spaces.

2. That diversity among both speakers and PCs be treated as a basic quality check, not an optional extra or a last-minute fix.

Speaking up can feel awkward, especially when omissions are framed as oversights. But silence signals acceptance, and acceptance ensures repetition.

If others on this list are willing to share strategies that have worked—especially around PC formation as well as speaker selection—I think that would be extremely valuable.

Best regards,
Valeria

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Saying good bye to Harold

 Harold wasn't ill, as far as I know. He seemed to be enjoying his life as an avant-guarde musician, and was due to perform two days (or something like it) after he died. I read it in the website of the venue when I tried to learn more. This seems so unfair! 

Harold A. J. M. Schellinx was very, very clever and a good person. He helped me a lot when we were both starting. I finished my doctorate earlier than him, because he did so much for his. I am still trying to learn some of the things he wrote in 1994! Last time I wrote to him, around 2005, I was trying to get him to publish his thesis in Lulu. Amazon said it had one copy for more than 200 dollars and I said it would be nice if he did republish it. He replied that he still had plenty of copies and if I knew someone who wanted it, I should give them his email. Fair enough.

Harold could have destroyed my career, if he wanted to. He found a big hole in my work and helped me to try to fill it. Which I did, many years later. Andreja Prijatelj was a common friend, who departed  earlier in 2002.

I started this post in September, when I heard the bad news from Jean-Baptiste, via Luiz Carlos. It hurt. Much more than when I heard about Thomas Streicher. At least I had had a chance to catch up with Thomas in Padova, to have lunch and chat about the world with him. I don't think he knew already about his disease. I didn't, for sure, and thought it was only a lovely chat after so many years apart. And that this would become more part of my life now that I only work on things I want to. Little did I know that this was the last time I would see him alive.

But Christmas is the season for ghost stories and for self-recrimination. And  I do have these in spades. I don't mean in epic proportions, like Dicken's `The Christmas Carol' Scrooge, but it feels really heavy right now. I guess it happens to everyone,  reason why the holidays can be so fun and at the same time so sad, so difficult to survive! All that I need to do is be less self-centered, think more of others, understand better what matters to them and act on it. It shouldn't be so hard. (One thing I like about myself is the very Brazilian habit of always thinking we can do it, that there is always new chances and new beginnings).

Ada Lovelace Day 2025

 

 

 Phew! I almost completely missed it! This year's Ada Lovelace heroes are Larisa Maksimova and Ewa Orlowska. Someone once said (and I repeated it dozens of times in talks and in writing) that starting a project is easy; difficult is keeping it up, year after year.  Maintenance is much harder than starting new things. It's not sexy, I can be very boring. I seem to be falling prey to this difficulty now. I have been doing Ada Lovelace Day posts since 2011. Nowadays it should be easier, since I can decide what I want to be working on. But instead it is turning harder: focusing on projects and finishing them off turns out harder if you make your own deadlines.

Anyways, as usual, better late than never. This year, I went back to basics and chose two mathematical logicians, as it was the original goal.  When I was growing up, I had the impression that many logicians, especially from the Iron Curtain countries, were women. They seemed established professionals; they looked much older than the corresponding authors from the West. They also morphed into a jumbled mass in my head. Now I realize the huge differences in subjects, approaches, cultures, etc.  Now I feel that I should try to learn the history of logic/mathematics and its nuances, checking out all the manipulations of  the winners, who write the (lack of) history. (Yes, we have a project on history of Mathematics in the BRICS countries, I have much to learn from my historian friends.) Anyways, here goes the two heroes of 2025:

 Larisa Lvovna Maksimova (5 November 1943 – 4 April 2025) was a Russian mathematical logician known for her research in non-classical logic. Sergei Odintsov (kudos to him!) edited  Larisa Maksimova on Implication, Interpolation, and Definability, Outstanding Contributions to Logic, vol. 15,  2018, a festschrift for her. I just bought the book and I hope to learn what she was doing with strict implication!

But to end on a positive note, the second hero is Stella Ewa Orłowska (born 1935),  a Polish logician. Her research centers on the concept that everything in logic and set theory can be expressed in terms of relations, and has used this idea to publish works on deduction systems and model theory for non-classical logic, and logics of non-deterministic and incomplete information. 

Professor  Orłowska has many  books under her name. She also has a festschrift book, pictured below. Just as well, as I could not find a picture of her today. But I do remember seeing several pictures in previous years. According to Google Scholar  professor Orłowska has a 2025 arxiv paper, joint work with Viktor Marek and Ivo Düntsch on Rough Sets. Wonderful to hear!

  

Women in Formal Mathematics 2024: A Weekend of Ideas and Community

On July 6–7, 2024, the Hausdorff Institute of Mathematics hosted the Women in Formal Mathematics workshop, a two-day event dedicated to showcasing and supporting women in formal proofs, logic, and automated deduction. The workshop was organized within the trimester program Prospects of Formal Mathematics, with support from Women in EuroProofNet 2024 (WEPN). 

 This blog post should probably have been written last year. But at the time, there were simply too many ideas and projects sparked during the program and immediately afterwards. I decided to wait until a report was requested — and in hindsight, the delay has been a gift. Looking back now brings the events into focus with an added layer of perspective, making the memories even more enjoyable to revisit. 

We were lucky to hear inspiring talks from five outstanding invited speakers — Ursula Martin (Oxford), Sandra Alves (Porto), Brigitte Pientka (McGill), María Inés de Frutos-Fernández (then at UAM), and Mateja Jamnik (Cambridge). Their contributions spanned big-picture reflections on why formalizing mathematics matters, as well as concrete research breakthroughs. Some of the talks are available to watch on the HIM YouTube channel.

Beyond the talks, the workshop created a welcoming space for connection — from early-career researchers meeting new mentors to a lively evening gathering that encouraged informal conversations. We are grateful to the HIM team, especially Silke Steinert-Berndt and Stefan Hartmann, for their support in making the weekend possible.

It was a memorable celebration of research, collaboration, and community — and we hope it will inspire similar initiatives in the future.

Intuitionistic Modal Logic: are you sure?

 I was always very keen on the idea that philosophical logicians and programming language designers interested in non-classical modal logics should talk to each other about their problems, about what kinds of  intuitionistic or constructive modal logics they would like to have and  why. 

Their goals are clearly different, but there is a large overlap in the mathematical contents of their common subject and because the communities largely ignore each other, they do not even know the basic results of the other `side' of the field.

 Because of this issue of people talking past each other I invested lots of effort into organizing IMLA (Intuitionistic Modal Logics and Applications), short meetings organized as workshops associated to bigger events like LiCS or FLoC or ESSLLI. The last IMLA happened in Toulouse in 2017. The picture below is the top of the  website, which I  lost when google sites decided to upgrade itself and trash out the old sites. I found the call for papers here.

Thank goodness there are proceedings of most, if not all, of the IMLA workshops:

• Fairtlough, Mendler, Moggi, Modalities in Type Theory (eds.), MSCS, (2001)
• de Paiva, Gore´, Mendler (eds), Modalities in constructive logics and type theories,  J of Log and Comp (2004)
• de Paiva, Pientka (eds.) IMLA 2008, Inf. Comput. (2011)
• de Paiva, Benevides, Nigam, Pimentel (eds.), IMLA 2013, ENTCS300, (2014)
• Alechina, de Paiva (eds.) IMLA2011, J. of Log and Comp, (2015)
• de Paiva, Artemov, Intuitionistic Modal Logic 2017, IfColog  Journal of Applied Logics, 2021.

 The IMLA meetings with respective invited speakers:

• FLoC1999, Trento, Italy, (Pfenning)
• FLoC2002, Copenhagen, Denmark, (Scott and Sambin)
• LiCS2005, Chicago, USA, (Walker, Venema and Tait)
• LiCS2008, Pittsburgh, USA, (Pfenning, Brauner)
• 14th LMPS in Nancy, France, 2011 (Mendler, Logan, Strassburger, Pereira)
• UNILOG 2013, Rio de Janeiro, Brazil. (Gurevich, Vigano and Bellin)
• ESSLLI2017, Toulouse, France (no special speaker)

 

 

 

 

Oh dear: my webpage in Bham is gone!

 I have been an Honorary Fellow at the School of Computer Science in the University of Birmingham, UK since 2000. I am still officially one  until 2028 and have an official letter saying it. But the University re-organized its website and I have not been able to get my webpage to resurface at all. The problem with this state of affairs is that many of my papers stopped  being available, which is a real heartache for me!

So this adds another item to the long list of boring tasks that I need to do. Some time. Soon. Much more important is to prepare my slides for the Oregon Programming Languages Summer School 2025. This is coming up real soon, so I should be doing my work, instead of writing blog posts. But I do feel very tired and jet lagged, as we came back from the UK the day before yesterday, so still waking up at 3 am and feeling wiped out at 4 pm.

But before I turn into a pumpkin, I will add here a photo from the book that Katerina, Tracy, Steve and Annie produce for Dick -- his Festschrift: "Semantics at the Crossroads: From Theoretical Explorations to Implementations." I am really proud of the book and of his work, and a tiny, little bit jealous, to tell the truth.

escrift