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    • CommentRowNumber1.
    • CommentAuthorUrs
    • CommentTimeSep 15th 2017
    • (edited Sep 15th 2017)

    At field (physics) I am beginning to write an actual introduction to the topic, now in a new section titled “A first idea of quantum fields”.

    This means to introduce the concept with precise detail, but in a simple context (trivial and bosonic field bundles over Minkowski spacetime, perturbatively quantized) that allows to get a quick idea of the idea of the concept of (quantum) fields as such, without being distracted by other details.

    So far I made it up to the derivation of the EOMs. Discussion of (deformation) quantization is to follow (maybe by tonight, depending on how much trouble I have with the trains) and I plan to sprinkle in the detailed example from scalar field in parallel with the abstract discussion.

    • CommentRowNumber2.
    • CommentAuthorDavid_Corfield
    • CommentTimeSep 15th 2017

    Did some proof reading.

    • CommentRowNumber3.
    • CommentAuthorUrs
    • CommentTimeSep 15th 2017

    Thanks, David!

    I did some more work in the Sandbox, but not ready yet.

    • CommentRowNumber4.
    • CommentAuthorUrs
    • CommentTimeSep 18th 2017
    • (edited Sep 18th 2017)

    I have expanded a little more in the Sanbox. But it turns out I need more time than I thought to finish typing this “First Idea of Quantum Fields”. Now I need to interrupt working on it until this Wednesday, and instead meanwhile I need to work further on S-matrix. Eventually the dust will settle…

    • CommentRowNumber5.
    • CommentAuthorUrs
    • CommentTimeSep 20th 2017

    Have been further working on it, but still not done.

    It finally dawned on me that it is pointless to try to squeeze this material into the “Idea”-section at field (physics). So I have declared it now a stand-alone chapter of geometry of physics. Now here:

    • CommentRowNumber6.
    • CommentAuthorTodd_Trimble
    • CommentTimeSep 20th 2017

    Let me say though that I think what you’re doing recently (the Insights article at Physics Forum, the articles on S-matrix and pQFT, etc.) is just great. For me it’s some of the most useful exposition I’ve ever seen for this area – far better than the books by Witten et al., this really is Quantum Fields for Mathematicians. Keep it coming!

    • CommentRowNumber7.
    • CommentAuthorUrs
    • CommentTimeSep 20th 2017

    Thanks for the feedback, Todd!

    When this chapter “A first idea of QFT” is closer to being stable (hopefully by tomorrow evening), I’d be very interested in hearing of your experience while reading through it, such as at which points the progression of the text seems unclear or maybe too unmotivated, or else maybe too pedantic or repetitive – whatever the case may be.

    • CommentRowNumber8.
    • CommentAuthorUrs
    • CommentTimeSep 21st 2017
    • (edited Sep 21st 2017)

    I have now made it to the description of the covariant phase space in section 7, and filled in full details on the Poisson bracket Lie (p+1)(p+1)-algebra in section 5. (here)

    Using this, next will finally be the discussion of the algebra of quantum observables in section 8. But not tonight.

    • CommentRowNumber9.
    • CommentAuthorDavidRoberts
    • CommentTimeSep 21st 2017

    I”m enjoying this too.

    • CommentRowNumber10.
    • CommentAuthorDavid_Corfield
    • CommentTimeSep 22nd 2017

    These examples may be combined: the mapping space [Σ,Ω n][\Sigma, \mathbf{\Omega}^n] is a kind of smooth classifying space for differential forms on Σ\Sigma

    Is ’on’ the right preposition here? Isn’t [Σ,Ω n][\Sigma, \mathbf{\Omega}^n] classifying Σ\Sigma-parameterized differential nn-forms?

    • CommentRowNumber11.
    • CommentAuthorUrs
    • CommentTimeSep 22nd 2017
    • (edited Sep 22nd 2017)

    Isn’t [Σ,Ω n][\Sigma, \mathbf{\Omega}^n] classifying Σ\Sigma-parameterized differential nn-forms?

    What you are thinking of are the plots

    U[Σ,Ω n] U \to [\Sigma, \mathbf{\Omega}^n]

    which equivalently are differential nn-forms on U×ΣU \times \Sigma, which one may think of as UU-parameterized differential forms on Σ\Sigma – since UU varies, while Σ\Sigma is fixed.

    The subtlety here, which I did not want to get into in this “first idea”-chapter, is that the actual classifing smooth space of differential forms on Σ\Sigma should assign to UU not all the differential forms on U×ΣU \times \Sigma, but just those which are plain functions with respect to UU (with no “legs” along UU). This genuine classifying space of differential forms on Σ\Sigma is the concretification

    1[Σ,Ω n]. \sharp_1 [\Sigma, \mathbf{\Omega}^n] \,.

    There is detailed discussion of this point at geometry of physics – differential forms, in the section Smooth moduli space of differential forms

    • CommentRowNumber12.
    • CommentAuthorUrs
    • CommentTimeSep 22nd 2017

    I’m enjoying this too.

    Thanks. If you have any comments (in particular critical comments) please do let me know.

    • CommentRowNumber13.
    • CommentAuthorDavid_Corfield
    • CommentTimeSep 22nd 2017

    I guess that’s a generalized element point of view, like we might have:

    In SetSet, we say that [A,2][A, 2] is the classifier of subsets of AA, rather than just the set of subsets of AA, because for any XX, X[A,2]X \to [A,2], picks out XX-parameterized subsets of AA.

    • CommentRowNumber14.
    • CommentAuthorUrs
    • CommentTimeSep 22nd 2017

    X[A,2]X \to [A,2], picks out XX-parameterized subsets of AA.

    Exactly! But this is not how you said it in #10. In your analogy Σ\Sigma there corresponds to AA here.

    Anyway, I suppose we perfectly agree on what’s going on.

    • CommentRowNumber15.
    • CommentAuthorUrs
    • CommentTimeSep 22nd 2017

    I have now spelled out the example of the free real scalar field alongside the development of the theory. Currently it culminates in a detailed derivation of the “causal propagator”/”Peierls bracket”/”Pauli-Jordan distribution” from first principles – here.

    • CommentRowNumber16.
    • CommentAuthorUrs
    • CommentTimeOct 4th 2017
    • (edited Oct 4th 2017)

    I have been working on the next section: “Gauge symmetries”.

    • CommentRowNumber17.
    • CommentAuthorDavid_Corfield
    • CommentTimeOct 10th 2017

    I imagine you’ll be editing offline, so I’ll note some typos here:

    to give first good precise idea; allowed to be globally hyperbolic Lorentzian manifold; family of smooth functions on Σ\Sigma [should be XX]; differential geoemtry; hence a field) [no opening bracket];

    A stray ’s’ appears in the right hand diagram after

    such that this system is compatible with the above projection maps, i.e. such that

    Not sure I see this:

    (j Σ (A)) *(f μν) =F μν =(dF) μν. \begin{aligned} \left(j^\infty_\Sigma(A)\right)^\ast(f_{\mu \nu}) & = F_{\mu \nu} \\ & = (d F)_{\mu \nu} \,. \end{aligned}

    Why does F μν=(dF) μνF_{\mu \nu} = (d F)_{\mu \nu}?

    • CommentRowNumber18.
    • CommentAuthorDavidRoberts
    • CommentTimeOct 10th 2017
    • (edited Oct 10th 2017)

    That last one might have to be (df) μν(d f)_{\mu\nu}

    • CommentRowNumber19.
    • CommentAuthorUrs
    • CommentTimeOct 10th 2017

    Thanks! All fixed now.

    (dFd F should have been dAd A :-)

    • CommentRowNumber20.
    • CommentAuthorUrs
    • CommentTimeOct 11th 2017

    There is now some first actual content in the next section: Reduced phase space.

    • CommentRowNumber21.
    • CommentAuthorUrs
    • CommentTimeOct 12th 2017
    • (edited Oct 12th 2017)

    I am exploring ways to best draw the big picture regarding the quantization of gauge theories. Here is one attempt:

    \,

    \,

    pre-quantum geometry̲ higher pre-quantum geometry̲ {Lagrangian field theory with implicit infinitesimal gauge transformations} explicategauge transformations {dg-Lagrangian field theory with explicit infinitesimal gauge transformations embodied by BRST complex } pass toderived critical locus {dg-reduced phase space embodied by BV-BRST complex } fix gauge { decategorified covariant reduced phase space } pass to cohomology { dg-covariant reduced phase space } quantize degreewise {gauge invariant quantum observables} pass to cohomology {quantum BV-BRST complex} \array{ \underline{\mathbf{\text{pre-quantum geometry}}} && \underline{\mathbf{\text{higher pre-quantum geometry}}} \\ \, \\ \left\{ \array{ \text{Lagrangian field theory with} \\ \text{implicit infinitesimal gauge transformations} } \right\} &\overset{ \text{explicate} \atop \text{gauge transformations} }{\longrightarrow}& \left\{ \array{ \text{dg-Lagrangian field theory with} \\ \text{explicit infinitesimal gauge transformations} \\ \text{ embodied by BRST complex } } \right\} \\ && \Big\downarrow{}^{\mathrlap{ \text{pass to} \atop \text{derived critical locus} }} \\ \Big\downarrow && \left\{ \array{ \text{dg-reduced phase space} \\ \text{ embodied by BV-BRST complex } } \right\} \\ && {}^{\mathllap{\simeq}}\Big\downarrow{}^{\mathrlap{\text{fix gauge} }} \\ \left\{ \array{ \text{ decategorified } \\ \text{ covariant } \\ \text{ reduced phase space } } \right\} &\underset{\text{pass to cohomology}}{\longleftarrow}& \left\{ \array{ \text{ dg-covariant} \\ \text{reduced phase space } } \right\} \\ && \Big\downarrow{}^{\mathrlap{ \array{ \text{ quantize } \\ \text{degreewise} } }} \\ \left\{ \array{ \text{gauge invariant} \\ \text{quantum observables} } \right\} &\underset{\text{pass to cohomology}}{\longleftarrow}& \left\{ \array{ \text{quantum} \\ \text{BV-BRST complex} } \right\} }

    Here:

    term meaning
    “phase space” derived critical locus of Lagrangian equipped with Poisson bracket
    “reduced” gauge transformations have been homotopy-quotiented out
    “covariant” Cauchy surfaces exist degreewise
    • CommentRowNumber22.
    • CommentAuthorUrs
    • CommentTimeOct 16th 2017
    • (edited Oct 16th 2017)

    I have now brought in the material which I had earlier written into separate entries, such as to have a skeleton for the complete notes (needs to be inter-connected and polished still, but should give an idea of the intended content): here.

    There are now 19 sections. I don’t think I could do with less, but also I shouldn’t have much more.

    I changed my strategy regarding introducing the required generalized geometry. Previously I had a lightning introduction to “functorial geometry” in the first section “Geometry”, but trying this out on readers like Arnold Nuemaier over in the PO-Insights discussion here I realized that this doesn’t work for the intended audience. So now I am instead trying to introduce the required geometry alongside as the corresponding physics gets introduced: first the “functorial geometry” in section 3 Fields then later the “higher geometry” in section 9 Gauge symmetries.

    This still needs a bit more work, I suppose. But maybe one can see if it is going in the right direction now.

    • CommentRowNumber23.
    • CommentAuthorUrs
    • CommentTimeOct 17th 2017
    • (edited Oct 17th 2017)

    David C: I see that you made an edit yesterday evening. To check what you did, I tried to click on “see changes”, but that produced a “502” error. Now I saved another version of mine and then similarly tried to see your changes via the History link here:

    https://ncatlab.org/nlab/revision/diff/geometry+of+physics+–+A+first+idea+of+quantum+field+theory/45

    but again I get a 502 error.

    I’ll report this to Adeel. Meanwhile: Is it easy for you to remember what you edited?

    • CommentRowNumber24.
    • CommentAuthorDavid_Corfield
    • CommentTimeOct 17th 2017
    • (edited Oct 17th 2017)

    Yes, you had an extra curly bracket in

    D μa ν αa ν,μ α+12γ α βγa μ βa ν γ(μν) D_\mu a_\nu^\alpha \;\coloneqq\; a^\alpha_{\nu,\mu} + \tfrac{1}{2} \gamma^{\alpha}{}_{\beta \gamma} a^\beta_{\mu} a^\gamma_{\nu} - (\mu \leftrightarrow \nu)

    so it wasn’t compiling.

    • CommentRowNumber25.
    • CommentAuthorDavid_Corfield
    • CommentTimeOct 17th 2017
    • (edited Oct 17th 2017)

    Oh dear, now I can’t see it compile here. It was the equation after

    consider the functions on the jet bundle given by

    [edit: silly me! I pasted in the original mistaken code.]

    • CommentRowNumber26.
    • CommentAuthorUrs
    • CommentTimeOct 17th 2017

    Thanks! I fixed it.

    When you say “doesn’t compile” do you mean that the whole page failed, or just the equation? That’s why I keep checking in the Sandbox, to ensure that the page as a whole comes out readably after saving. On my end it alsways did.(?)

    • CommentRowNumber27.
    • CommentAuthorDavid_Corfield
    • CommentTimeOct 17th 2017

    Just that equation.

    • CommentRowNumber28.
    • CommentAuthorUrs
    • CommentTimeOct 17th 2017

    I have started bringing in the example of the Dirac field (here). To that end I added to the section “Spacetime” discussion of spin, and to the section “Fields” discussion of supergeometry.

    Now there is need to harmonize some notation a bit better. But not today.

    Next I should try to sort out that issue with distributions as linear maps in the Cahiers topos (here).

    • CommentRowNumber29.
    • CommentAuthorDavidRoberts
    • CommentTimeOct 17th 2017

    At geometry of physics – A first idea of quantum field theory

    For 𝔤=𝔰𝔲(2)\mathfrak{g} = \mathfrak{su}(2) this is a field history for the gauge field of the strong nuclear force in quantum chromodynamics.

    This is a typo, no?

    Also: “ant-symmetry”, “so smal”

    In your “Remark 2.22. (two-component spinor notation)”, you write

    denoted (ξ a˙) a˙=1 2(\xi^{\dagger \dot a})_{\dot a = 1}^2

    which at first I thought was a power, but then I realised you meant a˙=1,2\dot a=1,2. This might be less confusing as the notation is already rather dense. Similarly for the left-handed spinor.

    In “Definition 2.28. (adiabatic switching)”, you have

    the vctor space space C (Σ)gC^\infty(\Sigma)\langle g \rangle spanned by a formal variable gg

    which apart from the typo was slightly confusing in the sense that you are, immediately before, talking about a cutoff function g swg_{sw}, so at first I guessed that gg here might be such a function, but I guess it is the gauge coupling? Might be worth disambiguating, or sign-posting here.

    an infinitesimally thickened Cartesian space n×Spec(A)\mathbb{R}^n \times Spec(A) is represented by a commutative algebra C ( n)Spec(A)AlgC^\infty(\mathbb{R}^n) \otimes Spec(A) \in \mathbb{R} Alg which

    that second Spec(A)Spec(A) should be just AA, I think.

    for each infinitesimally thickened Cartesian space matbbR n×Spec(A)\matbb{R}^n \times Spec(A)

    \matbb rather than \mathbb

    More: “the 1-dimensional even vector sspace”, “an super Cartesian space”

    super-commutative algebra C ( n)Spec(A)AlgC^\infty(\mathbb{R}^n) \otimes Spec(A) \in \mathbb{R} Alg

    again, AA, not Spec(A)Spec(A), I think.

    That’s down to the start of the section “Field variations”. More later, I hope.

    • CommentRowNumber30.
    • CommentAuthorUrs
    • CommentTimeOct 17th 2017
    • (edited Oct 17th 2017)

    Thanks for catching all this! All fixed now.

    In “Definition 2.28. (adiabatic switching)”, […] slightly confusing

    I have tried to improve the wording to clarify this. Now it reads like so:


    For a causally closed subset 𝒪Σ\mathcal{O} \subset \Sigma of spacetime say that an adiabatic switching function or infrared cutoff function for 𝒪\mathcal{O} is a smooth function g swg_{sw} of compact support (a bump function) whose restriction to some neighbourhood UU of 𝒪\mathcal{O} is the constant function with value 11:

    Cutoffs(𝒪){g swC c (Σ)|U𝒪neighbourhood(g sw| U=1)}. Cutoffs(\mathcal{O}) \;\coloneqq\; \left\{ g_{sw} \in C^\infty_c(\Sigma) \;\vert\; \underset{ {U \supset \mathcal{O}} \atop { \text{neighbourhood} } }{\exists} \left( g_{sw}\vert_U = 1 \right) \right\} \,.

    Often we consider the vector space space C (Σ)gC^\infty(\Sigma)\langle g \rangle spanned by a formal variable gg (the coupling constant) under multiplication with smooth functions, and consider as adiabatic switching functions the corresponding images in this space,

    C c (Σ) C c (X)g \array{ C_c^\infty(\Sigma) &\overset{\simeq}{\longrightarrow}& C_c^\infty(X)\langle g\rangle }

    which are thus bump functions constant over a neighbourhood UU of 𝒪\mathcal{O} not on 1 but on the formal parameter gg:

    g sw| U=g g_{sw}\vert_U = g \,

    In this sense we may think of the adiabatic switching as being the spacetime-depependent coupling “constant”.

    • CommentRowNumber31.
    • CommentAuthorDavidRoberts
    • CommentTimeOct 17th 2017

    Aha, that’s interesting. Both my guesses were wrong.

    More:

    Their variational derivative uniquely decomposes as 1) the Euler-Lagrange derivative δ ELEL\delta_{EL}\mathbf{EL} which is

    is (or defines) a prequantum [Lagrangian field theory]]

    and just before “Here η\star_\eta denotes the Hodge star operator of Minkowski spacetime.”

    one sees an equation where it is given as η\wedge_\eta \star. Also the sentence following seems to be truncated. Perhaps you were going to expand the example, or just meant to make a comment saying more general Lie algebras were possible.

    such that δEL\delta EL is proportional to the variational derivative of the fields (but not their derivatives[…]

    missing underscore.

    More later.

    • CommentRowNumber32.
    • CommentAuthorUrs
    • CommentTimeOct 17th 2017

    Thanks again!! All fixed now.

    • CommentRowNumber33.
    • CommentAuthorUrs
    • CommentTimeOct 27th 2017
    • (edited Oct 27th 2017)

    I have now considerably expanded the exposition of the underlying geometry.

    Now section 1. Geometry is, in principle, a self-contained (if terse) exposition of differential geometry over Cartesian spaces, and section 3. Fields develops from that in a similarly pretty self-contained way diffeological spaces, smooth sets, formal smooth sets, super smooth sets; all with some key examples and facts, following the demand of the development of the field theory.

    The first three sections are meant to go live on PhysicsForums-Insights in a few days.

    Further down the line I have been adding some basics on distributions as the multilinear observables on the super smooth set of field histories in 7. Observables – Polynomial observables

    When further editing 7. Observables – General observables I noticed that for EΣE \to \Sigma a supergeometric field bundle (such as for the Dirac field), then the tight identification of the mapping super smooth set

    [Γ Σ(E),] \left[ \Gamma_\Sigma(E), \mathbb{C} \right]

    “of observables” seems to requires a bit more work. It is easy to see that smooth functions on the diffeological space of sections of the odd-shifted field bundle induce generalized elements “at odd stage” in this super smooth set, but maybe I need to show that this construction exhausts that space.

    • CommentRowNumber34.
    • CommentAuthorDavid_Corfield
    • CommentTimeOct 29th 2017

    Is this open for editing, or are you working on the latest version offline?

    Typos:

    • $ |k|f α 1x 1 α 2x 2 α nx n, \frac{ \partial^{\vert k\vert} f }{ \partial^{\alpha_1} x^1 \partial^{\alpha_2} x^2 \cdots \partial^{\alpha_n} x^n } \,, $

    kk should be α\alpha.

    • $ n 2 f g n 1 gf n 2. \array{ && \mathbb{R}^{n_2} \\ & {}^{\mathllap{f}}\nearrow && \searrow^{\mathrlap{g}} \\ \mathbb{R}^{n_1} && \underset{g \circ f}{\longrightarrow} && \mathbb{R}^{n_2} } \,. $

    Should be n 3n_3.

    • $f:X n 1 n 2 f \colon X^{n_1} \longrightarrow \mathbb{R}^{n_2} $

    XX should be \mathbb{R}

    • Then, n𝕟\mathbb{R}^n \to \mathbb{n}

    should be \mathbb{n}

    • $C ( n)CAlg. C^\infty(\mathbb{R}^n) \;\in\; \mathbb{R} CAlg \,. $

    Why the ’C’ in ’CAlg’?

    • C^\infty8\mathbb{R}^{n_1}

    • not so inclined my ignore this

    may.

    • CommentRowNumber35.
    • CommentAuthorDavid_Corfield
    • CommentTimeOct 29th 2017

    Out of interest, does each session of your course cover about 1 section?

    • CommentRowNumber36.
    • CommentAuthorUrs
    • CommentTimeOct 30th 2017
    • (edited Oct 30th 2017)

    Thanks for the list of typos! Fixed now.

    I am not following the script linearly. I mean to optimize the text for reading.

    • CommentRowNumber37.
    • CommentAuthorUrs
    • CommentTimeNov 5th 2017
    • (edited Nov 5th 2017)

    Now on PhysicsForums-Insights: A first Idea of Quantum Field Theory.

    The chapters will be appearing incrementally. The first one is at

    Mathematical Quantum Feld Theory 1 – Geometry

    • CommentRowNumber38.
    • CommentAuthorUrs
    • CommentTimeNov 8th 2017
    • CommentRowNumber39.
    • CommentAuthorUrs
    • CommentTimeNov 20th 2017
    • (edited Nov 20th 2017)

    Meanwhile I have considerably boosted the chapters 7. Observables and 8. Phase space, using the all-important proposition 2.1 (and its enhancement) and lemma 2.5 from

    • Igor Khavkine,

      Covariant phase space, constraints, gauge and the Peierls formula,

      Int. J. Mod. Phys. A, 29, 1430009 (2014) (arXiv:1402.1282)

    which now appear as theorem 7.26 and theorem 8.7.

    It’s pretty neat how this part of the story comes together. Thanks to Igor.

    • CommentRowNumber40.
    • CommentAuthorUrs
    • CommentTimeNov 25th 2017

    finally chapter 9. Propagators is taking shape…

    • CommentRowNumber41.
    • CommentAuthorUrs
    • CommentTime5 days ago
    • (edited 5 days ago)

    Until now I could still save the entry A first idea of quantum field theory by repeatedly trying. After one or two dozen of attempts it would suddenly save (instead of giving the 502 error)

    But apparently this has reached a limit, today I haven’t been able to save my latest version, even after many attempts.

    Now I had the idea that I might try to split off each chapter as an include-file, save these separately (which works fine), and then include them all. Accordingly there is now a list of entries created titled

    But this trick turns out not to have any effect: the main file A first idea of quantum field theory, which is now mainly a list of include-commands, still produces errors when saving.

    • CommentRowNumber43.
    • CommentAuthorUrs
    • CommentTime5 days ago
    • (edited 5 days ago)

    That’s the entry I am talking about. Or was talking about, will have to abandon that project now.

    Check out the source of that entry. It ends now with the lines

      [[!include A first idea of quantum field theory -- Geometry]]
    
      [[!include A first idea of quantum field theory -- Spacetime]]
    
      [[!include A first idea of quantum field theory -- Fields]]
    
      [[!include A first idea of quantum field theory -- Field variations]]
    
      [[!include A first idea of quantum field theory -- Lagrangians]]
    
      [[!include A first idea of quantum field theory -- Symmetries]]
    
      [[!include A first idea of quantum field theory -- Observables]]
    
      [[!include A first idea of quantum field theory -- Phase space]]
    

    The goal would be to expand this list by the lines

      [[!include A first idea of quantum field theory -- Propagators]]
    
      [[!include A first idea of quantum field theory -- Gauge symmetries]]
    

    and make it save. But it doesn’t work.

    • CommentRowNumber44.
    • CommentAuthorUrs
    • CommentTime5 days ago

    Hah, I may have found a second-order trick that works around the bug:

    I first save the main entry with its full include-list while the entries-to-be-included are still empty! When that is saved, then I fill the content into the entries-to-be-included.

    • CommentRowNumber45.
    • CommentAuthorUrs
    • CommentTime5 days ago
    • (edited 5 days ago)

    Too bad, that doesn’t help either. While now the material saves, it still produces 502 errors when displaying.

    Okay, so that’s the end of it then.

  1. Oh I see, ’A first idea of quantum field theory’ was included as a redirect at ’geometry of physics – A first idea of quantum field theory’.

    What to do now?

    • CommentRowNumber47.
    • CommentAuthorUrs
    • CommentTime5 days ago
    • (edited 5 days ago)

    What to do now?

    What we should have done years ago: Somebody needs to set up a non-broken wiki and write a converter that turns our existing database of entries into whatever the new format is.

    The kind soul who wrote the converter from Instiki to Wordpress for me did so in two evenings, and it has all the functionality. This shows how easy this actually is for an expert (and how weird it is that after so many years Instiki is still so severely broken.)

    With so many computer-science-affine contributors here it would seem somebody should know somebody who would enjoy spending two evenings with migrating us to another working wiki platform?

  2. Given that we are hosted at Carnegie Mellon University, funded by the HoTT MURI grant, they must want nLab to function well. Could some extra funding be found for a software upgrade?

    • CommentRowNumber49.
    • CommentAuthorUrs
    • CommentTime5 days ago

    There are many possibilities and ideas, but somebody needs to take some action. If you have some free energy, you could try to follow up that suggestion by emailing, say, Steve Awodey.