XPost: sci.electronics.design
From: bill.sloman@ieee.org
On 22/02/2026 9:25 pm, J. J. Lodder wrote:
> Bill Sloman wrote:
>
>> On 21/02/2026 10:46 pm, J. J. Lodder wrote:
>>> Bill Sloman wrote:
>>>
>>>> On 21/02/2026 5:52 am, Ross Finlayson wrote:
>>>>> On 02/20/2026 10:31 AM, Bill Sloman wrote:
>>>>>> On 21/02/2026 3:47 am, Ross Finlayson wrote:
>>>>>>> On 02/19/2026 11:45 PM, Bill Sloman wrote:
>>>>>>>> On 20/02/2026 10:48 am, Ross Finlayson wrote:
>>>>>>>>> On 02/19/2026 11:19 AM, Bill Sloman wrote:
>>>>>>>>>> On 20/02/2026 2:44 am, Ross Finlayson wrote:
>>>>>>>>>>> On 02/19/2026 01:45 AM, Bill Sloman wrote:
>>>>>>>>>>>> On 19/02/2026 6:13 am, Ross Finlayson wrote:
>>>>>>>>>>>>> On 02/18/2026 11:06 AM, Ross Finlayson wrote:
>>>>>>>>>>>>>> On 02/17/2026 08:35 PM, Bill Sloman wrote:
>>>>>>>>>>>>>>> On 18/02/2026 5:37 am, Ross Finlayson wrote:
>>>>>>>>>>>>>>>> On 02/17/2026 09:47 AM, Thomas 'PointedEars' Lahn wrote:
>>>>>>>>>>>>>>>>> Ross Finlayson wrote:
>>>>>>>>>>>>>>>>>> On 02/17/2026 03:49 AM, J. J. Lodder wrote:
>>>>
>>>>
>>>>
>>>>> I.e., mathematics _owes_ physics more and better mathematics
>>>>> of continuity and infinity.
>>>>
>>>> Mathematics doesn't owe physics anything. Physics exploits tools
>>>> developed by mathematicians, which makes physicists customers for the
>>>> work of some mathematicians.
>>>
>>> That is quite arguable.
>>> Much of mathematics wouldn't exist
>>> without (what was once) new input from physics.
>>> Many a luminary, Von Neumann for example,
>>> has said that mathematics will go stale
>>> without regular fresh input from the natural sciences,
>>> bringing new needs.
>>>
>>>> A mathematical physicist like Paul Dirac is an interesting hybrid, but
>>>> his biography is titled "The strangest man".
>>>>
>>>> https://en.wikipedia.org/wiki/Paul_Dirac
>>>
>>> Why discredit him by calling him 'a mathematical physicist'?
>>> He was a theoretical physicist,
>>
>> He invented the Dirac function, and bra-ket notation. He was notably
>> more deft with math than most of his contemporaries.
>
> Arguably. The real inventor was Oliver Heavidise.
> (who loved to pester mathematicians with it)
>
> Dirac just gave it another, more elegant name. [1]
> ( \delta(x) versus D H(x) or 1/2 D \signum(x) )
>
> And that 'most of' will depend on how wide you want to draw the circle.
>
>> https://en.wikipedia.org/wiki/Bra%E2%80%93ket_notation
>
> Nothing but notation. You can do without just as well.
> Mathematicians object to it,
> because the notation assumes without proof that adjoints exist.
> (which often needs to be shown, by their standards)
>
>> He reconciled several ostensibly different quantum theories by pointing
>> out that they were notational variations of the same basic idea.
>
> Yes. But imho his most important contribution
> was getting quantum field theory started,
"Quantum field theory" is just words to me.
> [1] Dirac was an electrotechnical engineer by training.
> He must have known about Heaviside and his operational calculus.
Perhaps. He did his first degree at Bristol in 1921, and went on to do a
separate degree in math in 1923. Heaviside was a controversial figure,
and might not have been much cited at Bristol back then.
Looking at Heaviside's wikipedia page, I note that he was the first to
use the impulse function (now known as the Dirac function). If Dirac had
known much about Heaviside's work, he probably would have called it the
Heaviside function when he first used it.
--
Bill Sloman, Sydney
--- SoupGate-Win32 v1.05
* Origin: you cannot sedate... all the things you hate (1:229/2)
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