Saturation, torsion, and contorsion: Difference between revisions
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== Torsion == | == Torsion == | ||
'''Torsion''' is used to refer to the opposite of saturation, but only regarding comma bases; in other words, a comma basis is either saturated, or it ''has torsion''. | '''Torsion''' is used to refer to the opposite of saturation, but only regarding comma bases; in other words, a comma basis is either saturated, or it ''has torsion''. | ||
Torsion also refers to a similar situation that occurs for the list of commas defining a [[periodicity block]]; in fact, this was its original use case. | |||
The term torsion has been used since at least as early as 1932<ref>https://scholar.google.com/scholar?q=%22torsion+group%22&hl=en&as_sdt=0%2C5&as_ylo=1900&as_yhi=1940</ref><ref>https://math.stackexchange.com/questions/300586/where-does-the-word-torsion-in-algebra-come-from</ref> and came to RTT from the mathematical field of group theory. | The term torsion has been used since at least as early as 1932<ref>https://scholar.google.com/scholar?q=%22torsion+group%22&hl=en&as_sdt=0%2C5&as_ylo=1900&as_yhi=1940</ref><ref>https://math.stackexchange.com/questions/300586/where-does-the-word-torsion-in-algebra-come-from</ref> and came to RTT from the mathematical field of group theory. | ||