# Shelah’s Model without P-points– part 9

## Part 9: the main lemma ctd.

In short:

• Destroying P-points in any further $\omega^\omega$-bounding extensions.
• Second and final part of the proof.

Shelah's model without P-points part 9

Part 9 as PDF

Part 9 as Xournal-source

# The Mathematician’s Homepage — can it be more?

Yesterday I went on a rant about Keith Devlin’s homepage and twitter. That was, like all rants, a little unfair on him. I guess idols are always more disappointing. However, although the rant was triggered by that one tweet it had been building up over the last week because I was writing a longer piece for various reasons. So here it is.

I’m enamoured with mathematical blogs. Ever since we started mathblogging.org, I browse through a lot of blog posts each day and I’m thrilled: the creativity and quality of their content is simply amazing, every day.

## Old-school is just old

And yet, hardly any mathematician I personally know keeps a blog. But almost all of them keep a homepage. And usually it is abysmal.

You probably know what I’m talking about. All those handwritten html pages from the late 90s using all sorts of html-evils that have long been discarded (tables, frames, puffy cloud mosaic gif backgrounds).

If you’re lucky, the homepage will have a cv, some self archived papers (ranked by vanity impact factor of the journals) and possibly teaching material, if you’re unlucky, papers are posted as an impossible to compile TeX variant and not stored on the arXiv (“’cause it’s too hard…”). If you’re really out of luck, you’ll find bizarre personal interests, genealogies, baby pictures and breakfast habits.

Of course, you can get away with almost anything if your content is fantastic (cf. Doron Zeilberger). But most people’s websites are a complete waste and an insult to anyone visiting them.

Why such harsh words?

An elementary web design paradigm says there are only two scenarios: either you want to reach your visitor or your visitor wants to reach you. If a page is designed under the first scenario, it must draw the visitor in, usually with clear, simple design that immediately conveys to the visitor why they should spend more time on your page. Under the second scenario your visitor wants something from you. Then, and only then, can you ask them to ‘work harder’, jump through some menus, wade through long content etc.

So the criticism is simple: these old-school homepages follow the second scenario where they should follow the first. And this is, whether intentional or not, an unnecessary insult.

## The true social network is the www

Ever since I read this quote (I think it was on netzpiloten.de but had no luck googling…), I cannot get it out of my head:

“The true social network is the world wide web.”

What a statement! Read it again.

“The true social network is the world wide web.”

I cannot get enough of it. One more time.

“The true social network is the world wide web.”

The thing is, I truly believe this.

Instead of centralized, company controlled social network we need to take charge of our online identities and set up our personal websites to serve as a hub for our exchanges with other people, online and offline. That way, we are in full control of what we share with whom and for how long.

I’m intentionally phrasing this very abstractly because there is neither a simple nor a permanent solution. Whatever technology can be used for this right now, it will most likely be obsolete in 5 years. But one thing is clear: we need more advanced tools than mere handwritten html (unless you are an hmtl5 wizard).

## Technology independence

The best reason for switching from some external social network to your own page running a modern web technology is independence. You’re in full control of your data, you’re in full control of your technology. Whatever technology you choose, you’ll never have to be locked in again. Given an open source technology you can upgrade to whatever, whenever — no more begging some company to implement a feature. You find a better technology, you switch; no harm done.

Take me as an example. I started with a shitty html website on my university user page, ripping off a senior colleague’s page, replacing his name, office etc. with mine. After a while I added a simple oddmuse wiki on the side for teaching and organizing research notes. After a while, I started a blog on blogspot.com using tex4ht to create mathml-driven posts. After a while blogspot didn’t cut it anymore (MathJax came out but its cdn didn’t exist), I switched to a “static blog generator”, jekyll, and MathJax, hosted on my personal domain. After a while I changed the server from a regular web host to Google’s app engine (for convenience and speed). And soon I’ll be switching to wordpress the server will then be using BitNami on Amazon’s web service.

As harsh as I put it above, I actually think the authors of most handwritten html pages feel the same way about technology lock-ins as I do. It’s only that they’re experiencing a completely different kind of lock-in: laziness. It can be hard to switch to something new. I can almost hear them… “I can control everything through my beloved vim/emacs”. It is a lot like saying: I can typeset my mathematics so beautifully using movable types in my garage, why would I use a computer system like TeX…

In other words technology independence also requires a conviction to improve and change the technology. This might, in fact, be the bigger problem.

## The scientific “community”

The reason to switch is easy: Scientists and especially mathematicians stand to gain incredibly from a modern homepage with modern web technology because it has reached a level that enables us to make the “scientific community” a (virtual) reality.

The term “community” always struck me as inappropriate. The closest I ever felt to being part of a community was as a student in the early years of getting my Diplom. I was part of a cohort of fellow students, meeting many times a week, exchanging ideas, working on problems, helping each other out scientifically and also spending quality social time together.

The classical German PhD model I suffered through is the opposite, really. It was following the master/disciple model, in effect isolating a PhD candidate from almost everyone outside their work group. Creating and investing in a community was essentially discouraged. For example, I remember the opposition we encountered when we started a What-is-Seminar in Berlin; professors either ridiculed or directly opposed the idea of a grad-student-only seminar aimed at building a better community among PhD students across research areas. Well, the seminar is still going strong even after the original organizers left Berlin.

The point is: the scientific community is not anywhere near to being a reality. Beyond the dominant “community” that are personal friendships and collaborations, it is a weird combination of short visits (say, to give a talk at a seminar), conferences and a dysfunctional publish-or-perish system.

In short, scientific-social connections are not transparent, difficult to keep running and depend on pedigree more than shared interests. There is no such thing as a real community because people are, in general, not connected to each other. Communication among researchers, the quintessential part of community is severely lacking.

## Making scientific community a reality

The web, on the other hand, is the perfect tool to communicate and connect. Using modern web technology you can keep track of content, activities, meet up for text, audio and video interaction. You can communicate any level of research activity, from teaching to schedules to explanatory text to collaborations to real time interaction. Any variant, any speed any combination.

The web is the true social network since it allows but never forces you to be connected, and the immersion into the social interaction can be varied to any degree you feel comfortable. The technology for this is freely available (free as in freedom) and it only keeps getting better and better.

What is lacking is only the number of researchers taking the web seriously, taking themselves on the web seriously.

The advantage for mathematicians lies in the much higher potential compared to the natural sciences. Due to the abstract nature and the mostly text driven research, mathematicians have been using the net to for as long as it exists. From mailing lists to arXiv.org from Mathscinet to Mathoverflow, the net is not only an essential but, more importantly, an established tool. And yet, the developments of the last decade seem not to have caught on; blogging, video sharing, social networks and microblogging are used by very few researchers in their research related activities.

## The potential of WordPress

The question becomes: How can we convince a significant amount of researchers to take their online identity into their more active hands? For this we need a technology that is reliable, simple to set up and customize. Right now, I think content management systems are the best technology available; and my favorite is WordPress.

WordPress is usually not considered a CMS, but a blogging engine. Yet, it has developed into a versatile tool that can take things far beyond mere text publication. It’s power is its open source nature and the simplicity of extending it via plugins — of which there are a countless number. On top of that, there is the WordPress For Scientists group that focuses on researcher relevant developments.

The reason to prefer a blogging engine is simple: everybody supports trackbacks. Trackbacks are a very old feature amongst blogging engines. The basic idea is as follows: if you’re writing a blog post and somebody else picks up the topic and writes about it, it would be nice for you to know about this, to know that you have, in effect, inspired somebody to be creative. Since the second author will usually link to your post when picking it up, the blogging engines developed trackbacks as a way to exchange this information automatically. That is, the first blog would be informed automatically via the webserver of the second blog’s trackback mechanism that a certain post was picked up by somebody else.

For a scientist, this is, of course all too familiar, since the today’s publication metrics feature citation indices heavily. Of course, the average number of readers of a scientific paper is 5 (and the median is 1) and those readers will most likely not cite the paper.

But this low number does not mean much in terms of the scientific community. Often reading a paper will lead to a conversation with other researchers, most likely a short talk in your local seminar and definitely some rewriting on the reader’s part; so the reach is much higher. And yet, this information is neither available nor considered significant at all, even though it is a much bigger part of “doing research”.

After all, research is about failing. We read a paper, we rewrite it to make it understandable, we try to apply what we learn from it to other problems. And almost all the time, nothing comes from it. This failure has no place in our shiny-new-results journal tradition (please don’t think I don’t know that there are historic reasons for the current system. I do know; it just does not make it less bad now).

So, as a researcher, I dream of an online community that allows me to collect all interactions with my research: reading, criticizing, bashing, ranting, re-writing, improving, destroying. And a community that values my own activities.

## Are we there yet?

Coming back to WordPress and trackbacks, their potential becomes clear: making use of trackbacks and other linkback technologies could be the key for scientific communication online. Yes, there isn’t yet a perfect technical solution, yes it requires an effort on.

But if we started to use wordpress and regular trackbacks to publish our research activities right now, we all could already gain a huge part of the kind of information we keep wasting in the current system. We could get a chance to learn, improve, defend, humble or enjoy our own research together with everybody else. As a community. Finally.

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# Dear Keith Devlin

## Dear Keith Devlin,

I love your work. Really, I do. So please don’t take this rant the wrong way. I promise I’ll shut up after this one rant, I just really need to get this off my chest.

#begin rant

Do you know what work of yours I read first? No, it wasn’t your fancy new Fibonacci book. It wasn’t even the Math Gene book even though it really changed my way of thinking about mathematics. It was, in fact, “A weak version of $\diamondsuit$ which follows from $2^{\aleph_0} < 2^{\aleph_1}$”.

I’m guessing you wouldn’t have guessed that. This was the very first research paper I read and my first seminar talk as a Diplomkandidat in Munich (many, many moons ago). It literally changed my life because it marked my final “conversion” to set theory, and – much, much more importantly – indirectly introduced me to my partner. So, when I say I love your work, believe me, I really mean it. (which is probably the reason why I’m ranting so hard…)

## Seriously, what are you doing online?

You’re very active on the interwebs and intertubes. That’s awesome because too few mathematicians of your calibre are. But have you looked at your homepage at Stanford recently? I mean, you probably haven’t (a box with blue-grayish background, bright red border and purple text?).

You’re website is stuck in the 90s.

The thing is: you are doing awsome stuff! You’re giving away lots of information: you’re letting people know where you’re giving lectures, you’re sharing videos, sharing research. That’s exactly what I hope for when I visit a scientists homepage. But…

This might sound silly, but web technology has actually advanced since 1998. It now allows you to share content in such a way that people do not have to look up your homepage every other day to check whether there’s something new. It also allows people to connect with you and makes it easy for them to share your content with a much wider audience.

## Hipster webs

The thing is you should know better. You write on your homepage that you have a twitter account and a blog. That’s so Web 3.0! Well, unfortunately, it isn’t, because, well, you’re doing it wrong.

First off, you don’t even properly link to either of these on your homepage. Then your blog is not a blog. It’s a magazine column that has an rss feed. It is not a log and, more importantly, it does not allow for discussions, which is the essence of blogging. So, in reality, it’s just another website that happens to have an rss feed. That’s not a bad thing – it’s just not a blog.

And then there’s your twitter account. Did you know that your replies are not that visible in your subscriber’s streams unless you put something in front of the @? What’s left is a lot of advertisement… and this morning, you even got the self-advertising wrong!

I mean, in this tweet you actually seem to try to hide the fact that, once more, you’re essentially advertising your new book. Now, I’m fine with good advertising. But don’t hide it and, for goodness’ sake, include a bloody link! I mean, you’re advertising your segment on NPR about your book and I still have to google to actually listen to it?

You really expect me to?

As they say, the web has no fury like a nerd scorned (or something like that).

#end rant

So, please, install wordpress on your homepage and join conversations on twitter. It makes life so much better.

# Why I back Relatively Prime

On of the pleasures of running mathblogging.org is that you get to find out about immensely creative people working on new ways to make use of the web for mathematics.

## ACME Science

Only a few weeks ago, I rediscovered Samuel Hansen’s ACME Science podcast. I remember stumbling upon it very early on when we started building the database for mathblogging.org but for the longest time couldn’t see how a podcast could fit.

It did, however, keep popping back up because Samuel Hansen’s friend and Math/Maths podcasting co-host Peter Rowlett was included in our database from the very start (simply because I had been following his blog).

## Relatively Prime

So what’s Relatively Prime? Well, you should probably head over to ACME Science to watch the promo video. Don’t worry, I’ll still be here when you’re back. Can’t wait? Ok, very short version. Relatively Prime is Samuel Hansen’s Kickstarter project to make a podcast series about mathematicians and their work, interviewing people in person. In a way, I’d say he wants to take Strongly Connected Components to the next level – but it’ll be much more, I think.

SSC is one of the best on the web that I know. The idea is simple, interviews with interesting mathematicians – nothing new, right? Since Samuel Hansen is not exactly working for the BBC World Service, glamour mathematicians are not on his list. And somehow that’s exactly what makes his show excellent: He has a knack for choosing interview partners that you would not expect to find in any main stream (scientific) media.

Of course, it’s Hansen who really makes these interviews work. His podcasts are a perfect example of the incredible (and mostly still undiscovered) potential of how mathematicians can connect; on every level, trough the net. That’s the stuff we built mathblogging.org for!

I have only one criticism: more female mathematicians would not hurt the show. Maybe Relatively Prime will surprise me even more?

## Now you go and back it!

The great thing about kickstarter is you can give on the level you’re comfortable giving. Since you ask, of course I chose my backing level to maximize vanity under the restraints of my financial means But so can you! There are 20 days left to get this project funded – so head over there and pledge some money!

EDIT: Samuel Hansen corrected me via twitter: Relatively Prime will be audio only. I think I got it wrong because of the promo video. But who cares, it’s going to be awesome either way!

# Epub and mathematics

I had joined that group right away and had wanted to do some experiments for a while now. I have been falling in love with wordpress more and more and I will probably switch rather sooner than later. Then last week Lieven le Bruin released some of his posts as PDF and, upon my comments, also experimented with epub. But the discussion on his blog brought back the issue of mathematics in epub.

By the way, I’m also starting another experiment – writing a paper collaboratively using wordpress! This will hopefully mean I can share more experiences. The main tool for this is pandoc – a great tool for document conversion, especially if, like me, you love markdown. Pandoc will eventually help me convert markdown to LaTeX (for the final touches). I’ll write more about that at some other point.

Anyway, today I finally got around to experimenting with epub and wrote the following lines on the google group.

Hi.
I have been experimenting with Martin’s epub-export plugin and, as a mathematician, can’t really be happy. There seems to be no good way to export mathematics in the sense that I (and most others online) are too used to LaTeX syntax and MathJax these days.
From what I understand, the current situation is that the epub standard has a “should not”-rule for javascript inclusion and almost all applications block javascripts.
This might possibly change in the future since the epub3 draft contains a “could”-rule for javascript. From a math(jax) point of view, javascript would solve a lot of issues. So I had wanted to experiment for some time and finally got around to it – so I thought I should share this.

A while ago I found a promising story about javascript in epub. In particular, javascript seems to work in the iPad’s ebook app.
Today, I tried to use this knowledge to create some easy mathematics in epub and testing this with a friend’s iPad.

• Asciimathml inclusion “just worked” in the sense that adding the javascript file and adding the suitable line in the header of my test epub’s chap1.xhtml worked in the iPad app.
• MathJax inclusion via the CDN worked – that’s great news, since it keeps the file small (but somewhat disturbing since it means all kinds of evils are possible via external javascript)
• MathJax inclusion in the epub file failed. This is unfortunate. The size of the epub increases significantly (and the process takes ages with the 30.000 mathjax files), but from what I understand the file limit is 2GB, not 16MB…

So I have three questions:

1. Could anybody try to reproduce this?
2. Does anybody have thoughts on the problem of actual inclusion of mathjax?
3. Does anybody know an ebook reader outside of the ipad that tolerates javascript?

Thanks for any suggestions! Peter.

# Shelah’s Model without P-points– part 8

## Part 8: the main lemma

In short:

• Destroying P-points in any further $\omega^\omega$-bounding extensions.
• First part of the proof.

Shelah's model without P-points page 8

Part 8 as PDF

Part 8 as Xournal-source

# Shelah’s Model without P-points– part 7

My apologies for the blogging hiatus. Let’s continue.

## Part 7: switching filters

In short:

• From $u$ to $\{ \omega \} \otimes u$.

Shelah's model without P-points page 7

Part 7 as PDF

Part 7 as Xournal-source

# Shelah’s Model without P-points– part 6

## Part 6: properness ctd.

In short:

• Basic Properties:
• Grigorieff forcing and the Sacks variant are proper (part 2)

Shelah's model without P-points page 6

Part 6 as PDF

Part 6 as Xournal-source

# Shelah’s Model without P-points– part 5

## Part 5: properness

In short:

• Basic Properties:
• Grigorieff forcing and the Sacks variant are proper (part 1)

Shelah's model without P-points

Part 5 as PDF

Part 6 as Xournal-source

# Shelah’s Model without P-points– part 4

## Part 4: $\omega^\omega$-bounding

In short:

• Basic Properties:
• Grigorieff forcing and the Sacks variant are $\omega^\omega$-bounding

Shelah's model without P-points page 4

Part 4 as PDF

Part 4 as Xournal-source