> Using two distinct constants which differ only by a factor of two sounds more confusing than choosing either one and sticking to it.
Physics is incredibly unusual in that it has very few overloaded terms, and so almost everything that is expressed in daily use is expressed with as much precision and as little ambiguity as possible. Most scientific disciplines are not so lucky.
It does still happens in physics (h and h-bar, as noted in another response below), but it happens all the time in statistics, so much so that it's incredibly frustrating to read a new text for the first time.
đ? Probably refers to the error of a regression, assumed to have mean zero and be independent.
e? Uh-oh. Possibly refers to the error term in a regression, as above. But it could also refer to the residuals, which always have mean zero and are never independent. Very different.
ĂȘ? Okay, once I see this, I know that the author probably doesn't use đ as well, so this narrows it down somewhat. But not entirely.
And don't get me started about 'standard error'. I have heard that term used in reference to a sample mean, a sample mean divided by the square root of the population, or the standard error of a regression (which is more complicated than I care to describe in plain English).
Do you want to get started about economists, who often use Ï as a variable? Or computer scientists, who use it to refer to a process calculus?
How about ÎŁ, which can be used to indicate a sum, but can also be used to indicate a covariance matrix? Which, by the way, can also be expressed in terms of either S or Q, depending on who you ask.
Ooh! How about Î? That's the precision matrix, so it has to be precise, right? Well, yes, except that all we're doing is writing the inverse of ÎŁ, so it's an unnecesary letter altogether[1].
Right now, we're dealing only with conflicts within a given field, but we could open Pandora's box and talk about the fact that λ is an anonymous function in computer science, but a constant that (partially) defines the stationary point for a given optimization problem.
Or letters that look like each other - can you really tell the difference between Îœ and v? Or Ï and w? What about when I write them out by hand?
[1] Unless you're using the term to implicitly declare that the covariance matrix is invertible, but if you think that substituting one capital Greek letter for another is a clear way of telling me that a matrix is full-rank, we need to have a much longer conversation.
EDIT I must say, I'm very impressed that HN handled all that unicode beautifully. Kudos to pg (& co.?)!
"Right now, we're dealing only with conflicts within a given field, but we could open Pandora's box and talk about the fact that λ is an anonymous function in computer science, but a constant that (partially) defines the stationary point for a given optimization problem."
And it also represent a null character in linguistics, empty set in some set mathematics, null-pointer in some computer science texts, etc.
Physics is incredibly unusual in that it has very few overloaded terms, and so almost everything that is expressed in daily use is expressed with as much precision and as little ambiguity as possible. Most scientific disciplines are not so lucky.
It does still happens in physics (h and h-bar, as noted in another response below), but it happens all the time in statistics, so much so that it's incredibly frustrating to read a new text for the first time.
đ? Probably refers to the error of a regression, assumed to have mean zero and be independent.
e? Uh-oh. Possibly refers to the error term in a regression, as above. But it could also refer to the residuals, which always have mean zero and are never independent. Very different.
ĂȘ? Okay, once I see this, I know that the author probably doesn't use đ as well, so this narrows it down somewhat. But not entirely.
And don't get me started about 'standard error'. I have heard that term used in reference to a sample mean, a sample mean divided by the square root of the population, or the standard error of a regression (which is more complicated than I care to describe in plain English).
Do you want to get started about economists, who often use Ï as a variable? Or computer scientists, who use it to refer to a process calculus?
How about ÎŁ, which can be used to indicate a sum, but can also be used to indicate a covariance matrix? Which, by the way, can also be expressed in terms of either S or Q, depending on who you ask.
Ooh! How about Î? That's the precision matrix, so it has to be precise, right? Well, yes, except that all we're doing is writing the inverse of ÎŁ, so it's an unnecesary letter altogether[1].
Right now, we're dealing only with conflicts within a given field, but we could open Pandora's box and talk about the fact that λ is an anonymous function in computer science, but a constant that (partially) defines the stationary point for a given optimization problem.
Or letters that look like each other - can you really tell the difference between Îœ and v? Or Ï and w? What about when I write them out by hand?
[1] Unless you're using the term to implicitly declare that the covariance matrix is invertible, but if you think that substituting one capital Greek letter for another is a clear way of telling me that a matrix is full-rank, we need to have a much longer conversation.
EDIT I must say, I'm very impressed that HN handled all that unicode beautifully. Kudos to pg (& co.?)!