Phone Book's Fans: Shocking Claim on Torsion

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In summary, the conversation discusses a possible mistake made by the authors of a book on gravitation and gauge symmetries. It is pointed out that the authors may have been aware of theories with torsion, but the book was written before the proof was available. The possibility of a misstatement is acknowledged, but it is noted that the authors are experts in general relativity and may not have been as knowledgeable about theories with torsion.
  • #1
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Here's something for the phone book's fans to chew on:

Surprisingly, on page #1278, in the index entry "Torsion", the 3 authors claim that "(torsion) not present in affine connection if equivalence principle is valid" and hint further to page #250 where they don't debate on it.

However, this assertion is terribly wrong, as Milutin Blagoevic' quoting [1] on page #66 of his book ("Gravitation and gauge symmetries") states after proving.

Surely, they wrote the book 3 years before the proof, but anyways, how could they do that ? They were already aware of both Cartan's theory (GR with torsion) and Lorentz gauge theory pioneered by Utiyama in his groundbreaking article in 1956 and refined by Sciama & Kibble. :rolleyes:


[1]P von der Heyde [1975] "The equivalence principle in the [itex] U_{4} [/itex] theory of gravity", Nuovo Cim. Lett. 14, 250.
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  • #2
I guess MTW are humans too. Besides, they are experts for GR, but not for theories with torsion.
  • #3
Different parts of the book were authored by the three coauthors, so one of them might have referred to material discussed in chapters written by another of the trio.

MTW has very, very few misstatements (I haven't tried to verify the claim that you uncovered one, but this is certainly possible).

Chris Hillman

Related to Phone Book's Fans: Shocking Claim on Torsion

1. How does torsion affect phone book fans?

Torsion is a force that causes twisting or rotation in an object. In the case of phone book fans, torsion can cause the blades of the fan to rotate in an uneven or uncontrolled manner, leading to potential safety hazards.

2. What is the shocking claim about torsion and phone book fans?

The shocking claim is that phone book fans are more susceptible to torsion-related accidents compared to other types of fans.

3. What evidence supports this claim?

Studies have shown that phone book fans have a higher rate of torsion-related accidents compared to other types of fans. Additionally, the design of phone book fans, with their thin blades and lightweight construction, makes them more prone to torsion forces.

4. Can torsion be prevented in phone book fans?

Yes, torsion can be prevented in phone book fans by implementing safety measures such as using heavier blades and adding stabilizing features to the fan's structure. Regular maintenance and inspection of the fan can also help identify and prevent potential torsion issues.

5. Are there any safety concerns for using phone book fans?

While torsion is a potential safety concern for phone book fans, it is not the only one. The lightweight and flimsy construction of these fans can also make them more prone to overheating, electrical malfunctions, and other safety hazards. It is important to follow safety guidelines and use caution when using any type of fan.

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