- #1

Haorong Wu

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They look very similar. Are there some rules that I should use one of them in some specific cases?

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- Thread starter Haorong Wu
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- #1

Haorong Wu

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They look very similar. Are there some rules that I should use one of them in some specific cases?

- #2

berkeman

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They look very similar. Are there some rules that I should use one of them in some specific cases?

No they don't. Not when written like you did in Latex...

- #3

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[itex] \rho [/itex] and [itex] p [/itex], [itex] \chi [/itex] and [itex] x [/itex], [itex] \kappa [/itex] and [itex] k [/itex], [itex] \tau [/itex] and [itex] T [/itex],

[itex] \gamma [/itex] and [itex] Y [/itex] , [itex] \eta [/itex] and [itex] n [/itex], [itex] \beta [/itex] and [itex] B [/itex], [itex] \epsilon [/itex] and [itex] E [/itex],

and, finally, (iota) [itex] \iota [/itex] and [itex] i [/itex] and (omicron) [itex] \omicron [/itex] and [itex] o [/itex] and (upsilon) [itex] \upsilon [/itex] and [itex] u[/itex] or [itex] v [/itex].

If handwritten, the chance for confusion is higher.

What's sometimes annoying is having people call [itex] \rho [/itex] "[itex] p [/itex]", etc..

It's probably best to stick to common conventions.

I like to spell out the letter if I feel that confusion can arise.

e.g., the pressure [itex] p [/itex] and the density (rho) [itex] \rho [/itex] are related by [itex] p = p_0 +\rho g h [/itex]

- #4

jtbell

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It's the Westerners' revenge for having to learn hundreds of characters when studying Chinese.

- #5

jtbell

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1. In textbooks and in LaTeX, mathematical formulas use the Latin alphabet in a different font (typeface) than in ordinary print:

Math: ##a\, b\, c\, d\, e\, f\, g\, h\, i\, j\, k\, l\, m\, n\, o\, p\, q\, r\, s\, t\, u\, v\, w\, x\, y\, z##

Ordinary print: a b c d e f g h i j k l m n o p q r s t u v w x y z

2. Mathematical formulas often use the Greek alphabet which is

Greek math: ##\alpha\, \beta\, \gamma\, \delta\, \cdots##

You simply have to become familiar with the Greek alphabet and pay attention to characters which look similar to (but not identical with) Latin characters, e.g. ##\omega## "omega" versus ##w## "double-u" (in English; other languages have different names for it), or ##\rho## "rho" versus ##p## (p). My (American) students in introductory physics classes also often had trouble with these. Also with ##\kappa## "kappa" versus ##k## (k), and ##\alpha## "alpha" versus ##a## (a). It simply needs practice and memorization.

- #6

atyy

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How to distinguish ##r## and ##\gamma##, ##w## and ##\omega##, ##v## and ##\nu## and ##\upsilon##?

It is not possible except by knowing the convention and context. I had a lecturer who did not know or did not want to pronounce ##\xi## the conventional way, and called it "squiggle". It was fine as everyone understood the physics he intended to communicate.

- #7

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I must say that if I'm using ##v## for velocity I'll typically use ##f## for frequency instead of ##\nu## to avoid confusion. And I hate working with the dust stress-energy tensor because it's ##\mathrm{diag}(\rho,p,p,p)## and I have to be very careful not to mix up density and pressure.

I suppose that all I'm really offering is sympathy. You do get used to knowing that people use rho for density, and then you're primed to look for the difference (the top left of a ##p## is different to a ##\rho##).

- #8

jtbell

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- #9

Vanadium 50

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I've seen it used as a variable index in really gnarly equations.

- #10

Haorong Wu

- 387

- 85

[itex] \rho [/itex] and [itex] p [/itex], [itex] \chi [/itex] and [itex] x [/itex], [itex] \kappa [/itex] and [itex] k [/itex], [itex] \tau [/itex] and [itex] T [/itex],

[itex] \gamma [/itex] and [itex] Y [/itex] , [itex] \eta [/itex] and [itex] n [/itex], [itex] \beta [/itex] and [itex] B [/itex], [itex] \epsilon [/itex] and [itex] E [/itex],

and, finally, (iota) [itex] \iota [/itex] and [itex] i [/itex] and (omicron) [itex] \omicron [/itex] and [itex] o [/itex] and (upsilon) [itex] \upsilon [/itex] and [itex] u[/itex] or [itex] v [/itex].

If handwritten, the chance for confusion is higher.

What's sometimes annoying is having people call [itex] \rho [/itex] "[itex] p [/itex]", etc..

It's probably best to stick to common conventions.

I like to spell out the letter if I feel that confusion can arise.

e.g., the pressure [itex] p [/itex] and the density (rho) [itex] \rho [/itex] are related by [itex] p = p_0 +\rho g h [/itex]

I wonder whether there is a table listing convention usages.

After all, when I continue reading more and more textbooks, there are more and more symbols and quantities that I am not so familiar with as ##\rho## for density, ##p## for pressure, etc. It is difficult for me to clearly figure out which symbol I am encountered.

- #11

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A decent textbook should at least define its symbols and conventions... and this varies among specializations.I wonder whether there is a table listing convention usages.

After all, when I continue reading more and more textbooks, there are more and more symbols and quantities that I am not so familiar with as ##\rho## for density, ##p## for pressure, etc. It is difficult for me to clearly figure out which symbol I am encountered.

Not necessarily definitive... but possibly useful : https://physics.info/symbols/

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