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    • CommentRowNumber1.
    • CommentAuthorUrs
    • CommentTimeOct 26th 2011
    • (edited Oct 26th 2011)

    Hi everyone,

    tomorrow (in a dozen hours from now) I am giving a talk at Quantum Physics and Logic 2011 .

    This is required to be a beamer talk. So I have prepared some slides, titled

    This should be easy going, with a little bit of fun at the beginning.

    I’d be interested in whatever comment anyone here might have!

    • CommentRowNumber2.
    • CommentAuthorDavidRoberts
    • CommentTimeOct 26th 2011

    Very nice. I’m glad you are able to condense what seems to outsiders into an accessible talk. Small typos: on the slides defining the quadruple of adjoint functors for (oo-)cohesive toposes, your left-pointing arrows turn into ’hookleftarrow’s part-way through.

    • CommentRowNumber3.
    • CommentAuthorUrs
    • CommentTimeOct 27th 2011
    • (edited Oct 27th 2011)

    Thanks, David, for the feedback! Much appreciated.

    Those hookleftarrows appear intentionally. Secretly at this point I am speaking about the definition of local topos . But I thought I’d not make the technical details explicit and just sneak them in for attentive readers/listeners. Such as you! ;-)

    • CommentRowNumber4.
    • CommentAuthorDavidRoberts
    • CommentTimeOct 27th 2011

    My thought was that they should have been hookleftarrows all along, am I right?

    • CommentRowNumber5.
    • CommentAuthorDavidRoberts
    • CommentTimeOct 27th 2011

    Slides 31-36 have a floating comma that ends up separating a list on slides 37 and after.

    • CommentRowNumber6.
    • CommentAuthorTom Leinster
    • CommentTimeOct 27th 2011
    • (edited Oct 27th 2011)

    Quick comments:

    I thought the conversation between the physicist and the logician was hilarious.

    On page 38 (51 of 175), I'd change "may not be reversible" to "need not be reversible" or "might not be reversible". It's ambiguous: in old-fashioned or formal English, "may not be reversible" means "is not permitted to be reversible". ("May I come in?" "No you may not!") In contemporary, perhaps "incorrect", English, people generally use "may not" as a synonym for "might not", which is what you're doing here. So it's a matter of distinguishing between "obliged not to be reversible" and "not obliged to be reversible".

    • CommentRowNumber7.
    • CommentAuthorTobyBartels
    • CommentTimeOct 27th 2011

    This is required to be a beamer talk.

    So it’s required to be bad? Where’s Doron Zeilberger when you need him?

    :-P

    • CommentRowNumber8.
    • CommentAuthorUrs
    • CommentTimeOct 27th 2011
    • (edited Oct 27th 2011)

    Good morning.

    Thanks for all the comments!

    I have fixed that floating comma and the “may be/need be”-thing, thanks! I still need to think about what to do with the hookleftarrows (maybe over breakfast, time is getting short now). Thanks for highligting that this causes trouble!

    Concerning Zeilberger: yes, I have the same feeling. I had intended this originally as a blackborard talk. But two days ago we received an email which said something like that they expect everybody to use the beamer and warn that the available whiteboard is tiny.

    Personally, I find already the step from blackboard to whiteboard a step in the wrong direction. But clearly a majority thinks differently.

    • CommentRowNumber9.
    • CommentAuthorAndrew Stacey
    • CommentTimeOct 27th 2011

    That has to be one of the daftest rants I’ve read from DZ.

    I’ve lost count of the number of rambling, inane, crammed, ill-prepared, disorganised chalkboard talks that I’ve been to. I’m no logician, but the argument “So-and-so gave a great chalkboard talk, therefore chalkboard talks are the best” seems … dubious.

    Giving a beamer presentation (note: beamer, not powerpoint - I despise powerpoint) means:

    1. I have to actually prepare the entire talk in advance.

      How many talks have you been to where it’s clear that the speaker just thought they’d talk about some particular subject and stop roughly when the hour was up? (“roughly” being the operative word!)

    2. I have to think about what the audience can see at any one particular time.

      Because you can’t rely on saving bits of the chalkboard, you have to think carefully, “If I need to use this again, I’d better say it again.”. Relying on the audience remembering something that you said 5 minutes previously is dangerous ground, and just waving vaguely at a bit of the chalkboard where you wrote it 10 minutes ago isn’t much better because although the statement is still there, the notation that it relies on is probably gone.

    3. I’m much less likely to stray off-topic.

      This is one of my top hates about talks. It just gets interesting (or the opposite: you start to feel that it’s not too long until it’s all over) when Big Name in the front row asks something almost completely irrelevant. Speaker then tries to answer that question (which almost no-one else is actually interested in) and gets completely side-tracked. With a presentation, it’s much harder to get derailed.

    4. I’m much more likely to say something interesting.

      Let’s face it, most talks are memorable for only about 5 minutes. There are great talks that really tell you something, but the vast majority are some convoluted complicated explanation of some technical point in an article. They remind me of the graduate talks when I was doing my PhD: they were basically an excuse for the student to tell their supervisor what they’d been doing, which was great for the supervisor but rubbish for everyone else (so we staged a revolution, but that’s another story). Unless it’s one of those Great Talks (and if you’re not sure, then it isn’t), the talk should essentially persuade me to read your paper. That’s it. Leave the complicated stuff for the paper - if I’m sufficiently interested, then I’ll learn it there; if I’m not sufficiently interested then don’t bother telling me about it in the talk!

    I’d also much rather listen to a beamer presentation than a chalkboard talk, for very similar reasons.

    I gave my first beamer presentation under similar circumstances: a few days before the conference we were told that there was no chalkboard and only a small whiteboard (turned out this was wrong). I made a lot of mistakes, but I still think that I gave a much better talk than I would have done if it had been a chalkboard talk because I was forced to think about the above things.

    Yes, there are awful beamer presentations. But I think that the people who give awful beamer presentations are equally likely to give awful chalkboard talks. And also as it’s a fairly new thing (for mathematicians, at any rate) a lot of the “good techniques” haven’t yet gotten into our blood. So we don’t know how to do it properly. All mathematicians should be forced to read the entire beamer manual, then there’d be a dramatic improvement in the standard of talks (to be clear, I don’t necessarily agree with all of the advice that Till Tantau gives, but if someone gives you advice and you decide to do otherwise, at least you’ve been forced to think about it).

    Lastly, the statement:

    Personally, I find already the step from blackboard to whiteboard a step in the wrong direction.

    is actually a damning indictment of the standard of talks that we give to each other. If the difference between a chalkboard and a whiteboard actually makes a difference to the quality of the talk, then it was an awful talk to begin with. Someone who hasn’t learnt how to write clearly and legibly on a whiteboard should not be giving talks using any medium.

    I’m not going to apologies for the rant - since someone mentioned DZ’s rant, it seemed appropriate.

    As a final word, if this weren’t a beamer presentation, how would the rest of us get to know what you intend to say?

    • CommentRowNumber10.
    • CommentAuthorUrs
    • CommentTimeOct 27th 2011
    • (edited Oct 27th 2011)

    Oh, Tom, and thanks for the feedback on the dialogue.

    Originally I had one more piece in there, which was driven by the different meanings of the word signature in logic and in physics. The logician would ask: “Wait, let’s start at the beginning, what is the signature (in logic) of your theory?” And then the physicist would cry out: “Lorentzian signature, of course!”

    But then after a while I was getting the feeling that this is too much slapstick with too little content. But privately I am giggling about the idea from time to time ;-)

    • CommentRowNumber11.
    • CommentAuthorMike Shulman
    • CommentTimeOct 27th 2011

    @Andrew #9: Hear, hear! I agree entirely with almost everything you said, with two caveats.

    First, I don’t think that beamer is always better than chalk. I think beamer is hands-down better for any talk half an hour or less, because in a short talk all you can hope to convey is ideas and beamer is much better for that. But if you have an hour, then you can hope to go through a medium-length argument and get the audience to follow it, and I think that’s pretty hard to do with beamer because of the small amount of information visible at any one time. Also, chalk is more flexible: you can easily respond to questions by writing more things you didn’t plan on having to say, or rearrange the talk in the middle because of what the audience wants. Obviously that flexibility is rope to hang yourself with, but if you know what you’re doing it can be a big advantage. Also, there is difference in context between conference talks and seminar talks; I think chalk fits better with the seminar atmosphere and beamer better for the conference. Departmental colloquia are somewhere in between.

    Secondly, I can’t stand whiteboards. (-: Maybe the quality of the talk shouldn’t be affected by black vs white, but neither should the quality of the talk be affected by, say, loud construction noise outside, or a broken heating system that makes everyone’s teeth chatter – and nevertheless, those would negatively affect my overall experience.

    But I don’t understand the statement “I find already the step from blackboard to whiteboard a step in the wrong direction” – there’s no sense I can think of in which that step is in anything like the same direction as the step from black/white-boards to beamer, so what does the rightness or wrongness of one have to do with the other?

  1. I loved the dialogue at the beginning! I hope you get a good laugh.

    Here are my initial impressions:

    I found the green on the slides starting around page 70 or so to be difficult to read on my computer. When it is projected through a beamer it will be totally impossible to see (tip from experience!).

    Is this a one hour talk? 116 slides is really a lot, even accounting for the “dynamics”. It feels more like an hour and a half of content. Is there any way to trim some of the details in parts II and III? Sometimes less is more.

    • CommentRowNumber13.
    • CommentAuthorAndrew Stacey
    • CommentTimeOct 27th 2011

    Mike, I accept your caveats. Your rudimentary classification of talks is good - I’d quite like to see a more refined classification! I think I’d put seminar talks still in the better-with-beamer category and put seminar series on the other side of the line. That’s partly because the majority of hour-long seminar talks that I’ve been to would have been far better as half-hour talks. I don’t think that an hour is a good length of time for a talk: it’s not enough or it’s too much. (A colleague once said that in an hour-long talk, 20 minutes should be for everyone, 20 minutes for those in your field, and 20 minutes for the experts. At the time, I thought that reasonable. Now, I think it’s appalling.)

    Chalk is more flexible.

    Tried a graphics tablet? Or an iPad? Seriously, it makes a huge difference.

    but if you know what you’re doing

    Aye, but thereby hangs the rub. Too few do know what they’re doing.

    Secondly, I can’t stand whiteboards.

    I actually have a similar reaction, though I think it’s more due to the fact that I’ve seen more awful whiteboard talks than chalkboard talks.

    What I’d really like to see in this debate is something beyond “I like” or “I don’t like” or “in an ideal world”. What, actually, is it about a chalkboard talk that means that many people think it better than a beamer talk? The number of good or bad talks is neither here nor there for that. I still, even though I now use beamer for everything, feel that there’s something missing from my beamer presentations that would be present in a chalk talk. But unless I can actually identify what it is, I’m not going to swap back. And if I can identify it then maybe I can figure out a way to include it in the beamer presentations.

    So I’d love it if those that prefer chalk to projector could explain exactly what it is that they prefer.

    (I had a “technology failure” in a lecture this semester and had to give the lecture using chalk. The response was, “Stick to the projector.”)

    • CommentRowNumber14.
    • CommentAuthorUrs
    • CommentTimeOct 27th 2011
    • (edited Oct 27th 2011)

    Hi Chris,

    thanks for the comments.

    I found the green on the slides starting around page 70 or so to be difficult to read on my computer. When it is projected through a beamer it will be totally impossible to see (tip from experience!).

    Hm, okay. I did display well, though.

    Is this a one hour talk?

    Yes.

    116 slides is really a lot, even accounting for the “dynamics”. It feels more like an hour and a half of content. Is there any way to trim some of the details in parts II and III? Sometimes less is more.

    You did notice the built-in shortcuts? The talk took them all. So I finished in leisurely pace after 45 minutes. Then the expected questions came and so I moved to the addendum and pointed out some technicalities there.

    I am being told it came across well.

    • CommentRowNumber15.
    • CommentAuthorUrs
    • CommentTimeOct 27th 2011

    Hi Andrew,

    What I’d really like to see in this debate

    How about opening a new thread for your debate?

    • CommentRowNumber16.
    • CommentAuthorjim_stasheff
    • CommentTimeOct 27th 2011
    In re: the vast majority are some convoluted complicated explanation of some technical point in an article. They remind me of the graduate talks when I was doing my PhD: they were basically an excuse for the student to tell their supervisor what they'd been doing,

    that type should be for thesis defense IF required
    graduate student talks should be training for giving good (job worthy) talks
    video taping as here at Penn wouldn't hurt


    which was great for the supervisor but rubbish for everyone else (so we staged a revolution, but that's another story). Unless it's one of those Great Talks (and if you're not sure, then it isn't), the talk should essentially persuade me to read your paper. That's it. Leave the complicated stuff for the paper - if I'm sufficiently interested, then I'll learn it there; if I'm not sufficiently interested then don't bother telling me about it in the talk!

    Yes, BUT rather the talk should essentially persuade me that there's something of *possible* interest
    • CommentRowNumber17.
    • CommentAuthorTodd_Trimble
    • CommentTimeOct 27th 2011

    I haven’t given a talk in front of mathematicians for 10 years now, but still…

    The obvious danger of using slides or beamer or power point is that one tries to say too much. With chalk, you are presenting a flow of ideas and reasoned discourse in “real time”. I’m not sure how eloquently I can put this, so maybe I can just refer to what Rota says about chalk talks in Indiscrete Thoughts?

    I sense there is greater chance for spontaneity in chalk talks, that they lend themselves less to being prefabricated. One can make a quick change of plan in response to how it is playing to the audience. There is something a little bit thrilling about the performance of a good chalk talk which can’t be captured in the same way with pre-prepared notes.

    • CommentRowNumber18.
    • CommentAuthorAndrew Stacey
    • CommentTimeOct 27th 2011

    How about opening a new thread for your debate?

    Ouch! Sorry.

    Okay, to get it back on track, now that you’ve given the talk, what would you do differently?

    • CommentRowNumber19.
    • CommentAuthorUrs
    • CommentTimeOct 27th 2011
    • (edited Oct 27th 2011)

    now that you’ve given the talk, what would you do differently?

    Dunno. I liked it. The people who approached me afterwards liked it. Nobody who didn’t like it has approached me yet. Be the first!

    • CommentRowNumber20.
    • CommentAuthorAndrew Stacey
    • CommentTimeOct 27th 2011

    Be the first!

    I can’t - I wasn’t at the talk.

    There are certainly things in the PDF that I looked at (it may have changed since I looked) that I thought that I wouldn’t do that way. Some are things that I’ve tried, but decided that they just don’t work. However, this is all very subjective and is as much to do with how I talk as what’s on a slide. So I thought I’d ask you first for what you thought, then I might be able to give some suggestions (might not, there’s no guarantee) on other things you could try. Me looking at the PDF and saying, “I wouldn’t do this, that, or the other” might be helpful, but it also might be highly irritating and come over as quite condescending! But I could do that, if you realise from the outset that I’m imagining me giving the talk and thinking what would or wouldn’t work for me.

    Dunno. I liked it.

    Good! But surely there’s something you felt could have gone better.

    The people who approached me afterwards liked it.

    Biased sample, I’m afraid.

    • CommentRowNumber21.
    • CommentAuthorDavidRoberts
    • CommentTimeOct 28th 2011

    @Andrew #20 - are you being politic or obfuscating? :P

    As far as there being too many slides, you can discount the opening discussion, which takes up a lot, because one only needs 5-10 seconds per slide there. But as the talk is past, this point is moot.

    • CommentRowNumber22.
    • CommentAuthorTobyBartels
    • CommentTimeOct 30th 2011

    How about opening a new thread for your debate?

    Done.

    • CommentRowNumber23.
    • CommentAuthorTobyBartels
    • CommentTimeOct 30th 2011
    • (edited Oct 30th 2011)

    Whoops, Andrew already did that, and I missed it! (But actually his thread is not quite the same topic.)

    • CommentRowNumber24.
    • CommentAuthorAndrew Stacey
    • CommentTimeOct 30th 2011

    David (#21): Neither. I know that if I gave that talk then certain things would not have worked and I know what I would have done better, but I didn’t give this talk. I’m happy to give some advice on how it could have been done differently, but for that to be useful then the things that wouldn’t have worked for me have to be the same as the things that Urs thought didn’t work for him.

    As an example of the sort of thing that I mean, I find that in my lectures then the dialogue thing doesn’t work. I end up reading what’s on the screen at the same time as the students, and that just gets confusing. So when I have a dialogue of that sort then I don’t put it on the screen but just act it out.

    But I get the feeling that Urs isn’t going to give another beamer talk if he can possibly avoid it! So there’s not actually a lot of point in me saying anything about it, especially given that Toby’s thread is a good place for gathering general ideas and my thread for gathering evaluation ideas.