Finally onto Chapter 3,

Second Order Typed Lambda Calculus

#maths #cs

Help 😶‍🌫️!

The textbook says that types don't matter in β-reduction.

I've been bashing my head for 3 days and still can't see it.

In the following

(λx:σ.M) N

surely the type of N must match the type of x ??

When the textbook talks about β-substition (not reduction) then it says types matter because you can't substitute A for B if the types don't match.

What am I missing?

#maths #cs

Games Convention 2005 – Die Magie von Leipzig

Vom 18. bis zum 21. August 2005 hatte die Leipziger Games Convention, Europas größte Computer- und Videospielmesse, ihre Tore zum bereits vierten Male für alle Neugierigen, Videospielsüchtigen oder Branchenkenner geöffnet.

https://www.videospielgeschichten.de/games-convention-2005-die-magie-von-leipzig/

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The University of Manchester joins two new national research hubs to drive sustainable manufacturing

Advanced materials We’re home to 700 materials experts, revo…
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https://www.europesays.com/uk/196859/

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📰 "Higher-Oder Splitting Schemes for Fluids with Variable Viscosity"
https://arxiv.org/abs/2506.14424 #Physics.Comp-Ph #Physics.Flu-Dyn #Pressure #Math.Mp #Math-Ph #Matrix #Cs.Ce

When I was in #CS grad school, back in the early 1990s, #wavelets were hot in 3D volumetric CG—oh, those SIGGRAPH symposia on the topic. At the same time in #EE, loads of papers were published on their efficacy in DSP. Just about everyone in EE and CS seemed to have published at least one paper on wavelets. Fun times. But the current state of wavelet academic #research seemed to have dried up.

I don't quite understand why wavelet transform has not supplanted Fourier transform in many #engineering and #computing application domains, considering its estimable time-frequency locality and its prodigious multi-resolution analysis capabilities, compared to Fourier analysis.

I am but a mere "maths carpenter". So, what am I missing, I wonder.

New work:

Distributed Transaction Patterns

https://github.com/ha1tch/dxp/blob/main/README.md

A framework for understanding and implementing distributed transaction patterns through a phase-based spectrum approach.

The DXP documentation is organized as a progressive journey through distributed transaction patterns.

#DistributedSystems #compsci #cloud #cs #foss #golang #natsio #oss #OpenSource

Michael D. Adams is looking for a post-doc to join him in Singapore on a project related to programming with fixed points:
https://michaeldadams.org/hiring/

Should be a fun PL project and a good opportunity to work and live in a cool city. #postdocjob #phd #cs #pl

📰 "Higher-Oder Splitting Schemes for Fluids with Variable Viscosity"
https://arxiv.org/abs/2506.14424 #Physics.Comp-Ph #Physics.Flu-Dyn #Pressure #Math-Ph #Math.Mp #Matrix #Cs.Ce

@jnpn There is probably an alternative universe where Brainfuck is studied and admired like Lambda Calculus by #cs people

I have long suspected that any language with if's and loops would be Turing complete, turns out there was a proof for that all along...

https://en.wikipedia.org/wiki/Structured_program_theorem

#programming #cs

Olga Carmona de plus en plus proche des Féminines du PSG –

Afin de concurrencer l’Olympique Lyonnais, les Féminines du PSG souhaitent se renforcer. Elles ser…
#Paris #FR #France #Actu #News #Europe #EU #actu #ActuParis #Actualités #ActualitésParis #canalsupporters #Carmona #CS #europe #feminines #FémininesduPSG #fémininespsg #mercato #mercatopsg #NewsParis #OlgaCarmona #ParisNews #parissaint-germain #parissg #psg #psgfeminin #realmadrid #Républiquefrançaise
https://www.europesays.com/fr/183302/

Why is there no consideration of base cases ?

This is the textbook's explanation of "structural induction". The subsequent worked examples don't refer to base cases either.

Is it because they are always trivially true? I doubt this, myself.

#maths #cs

currently learning about "structural induction"

my understanding (not 100% sure)

* We want to prove a property P for a λ-term E.

* E is constructed using a set of construction rules.

* So it must have been constructed from a term D by applying a construction rule.

* Induction hypothesis (IH) is that P is true for D.

* If we can prove that P applies to E by virtue of the IH and a property of the construction rules..

.. we've proven P is true generally.

Is that right?

#maths #cs

Sometimes, #deconvolution is used by #CS folks to mitigate noise and distortion in an image, provided the characteristic function of the interference source can be measured (or modelled).

I wonder if #radar #EE folks have tried deconvolving the reflected signal with a measured (or modelled) topography of the operating area, so as to cure the ills caused by the ground clutter.

#DSP #DIP

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📰 "Mathematical Modelling of Mechanotransduction via RhoA Signalling Pathways"
https://arxiv.org/abs/2501.04407 #Mechanotransduction #Physics.Bio-Ph #Q-Bio.Cb #Math.Na #Cs.Na #Cell