robphy's latest activity
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robphy replied to the thread Graduate What Exactly Is The Physical Content Of Maxwell's Equations?.In my websearch for conventions in Geometric Algebra, I stumbled upon two vocal critics of GA (listed below). Since I am just learning... -
robphy replied to the thread Graduate What Exactly Is The Physical Content Of Maxwell's Equations?.From an old thread of yours on Geometric Algebra...
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robphy replied to the thread Undergrad Raising and lowering indices using metric tensor.Yes. So, one can conclude (again) the various expressions obtained are equal.
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robphy replied to the thread Undergrad Raising and lowering indices using metric tensor."Raising" and "lowering" are just notational shortcuts that hide the [invertible] metric. How would you evaluate ##g_{\mu \nu} \left(...
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robphy replied to the thread Music Cover songs versus the original track, which ones are better?.(2026) audrey123talks - #Slayer - War Ensemble cover guitar and lefty bass +#スレイヤー [You can hear the bass more clearly in the Mar 2025...
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robphy reacted to Hornbein's post in the thread Music Cover songs versus the original track, which ones are better? with
Like.
The orig seems #1 to me. -
robphy replied to the thread Music Cover songs versus the original track, which ones are better?.(2026) Maya Neelakantan (12 years old) - War Ensemble — Slayer | Guitar Riffs + Jeff Hanneman Solo Tribute see also Maya Neelakantan...
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robphy replied to the thread Music Cover songs versus the original track, which ones are better?.https://en.wikipedia.org/wiki/You%27re_No_Good NEW * You're No Good - Linda Ronstadt {Stereo} 1974 Van Halen You're No Good live...
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robphy reacted to Ibix's post in the thread Undergrad The paradox of symmetrical time dilation with Like.
Seen in terms of geometry, it is closely analogous to two cars driving at equal speeds ##v## down straight roads that make an angle...
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robphy replied to the thread Graduate Can a causal or time-like structure emerge without assuming a metric?.Although this has some overlap with causal structure and relativity, your specific questions are more about the mathematics rather than...
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robphy replied to the thread Graduate Can a causal or time-like structure emerge without assuming a metric?.I use -- in Microsoft Word and it converts to the em-dash there. But how do you do it with this website's interface in Chrome or Edge...
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robphy replied to the thread Graduate Can a causal or time-like structure emerge without assuming a metric?.By the way, how you do type that dash ? I can't find it on my keyboard.
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robphy replied to the thread Graduate Can a causal or time-like structure emerge without assuming a metric?.So, can you specify by what you mean by "something more primitive" than Szekeres' signal relation S which "is reflexive, but not...
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robphy replied to the thread High School Is there anything in the Universe that is not fundamentally made up of matter?.Clearly, we are not all using the same definitions. So there is some ambiguity. And words are imperfect. So, it seems the question is...
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robphy reacted to sbrothy's post in the thread High School Is there anything in the Universe that is not fundamentally made up of matter? with
Haha.
I'm surprised that no one has yet to point out that it may not really matter that much. But then again that joke is so low-hanging and...