# What is the meaning of doublestruck E symbol?

• Dec 27th 2011, 11:56 AM
corsica
What is the meaning of doublestruck E symbol?
In mathematical literature I came across an equation where a doublestruck E symbol is used (last equation in the picture below).

Attachment 23139

I don't have the faintest clue what the doublestruck E means. I'm guessing it denotes some kind of function? I've checked the entire document and it offers no explanation what so ever.

Does any of you have any idea what the doublestruck E means?
• Dec 27th 2011, 12:02 PM
Plato
Re: What is the meaning of doublestruck E symbol?
Quote:

Originally Posted by corsica
In mathematical literature I came across an equation where a doublestruck E symbol is used (last equation in the picture below).
Attachment 23139
I don't have the faintest clue what the doublestruck E means. I'm guessing it denotes some kind of function? I've checked the entire document and it offers no explanation what so ever.
Does any of you have any idea what the doublestruck E means?

I don't know what it means there either.
But in that is just a type-face called Bold-Blackboard.
\$\displaystyle \mathbb{ABCDEF}\cdots\$
• Dec 27th 2011, 12:10 PM
corsica
Re: What is the meaning of doublestruck E symbol?
Thanks for the reply Plato. Yeah, the way it's typed it could even be just a variable (although I doubt this, the document does have a pretty extensive nomenclature and there is no \$\displaystyle \mathbb{E}\$ listed in it).

I was kinda hoping that \$\displaystyle \mathbb{E}\$ would be a commonly accepted (but not often used) notation for a certain function.
• Dec 27th 2011, 12:36 PM
corsica
Re: What is the meaning of doublestruck E symbol?
Finally, I've found the answer in another mathematical article. Apparently the \$\displaystyle \mathbb{E}\$ denotes an Entier function.
• Dec 27th 2011, 01:49 PM
HallsofIvy
Re: What is the meaning of doublestruck E symbol?
Okay, don't leave us guessing- what is the "Entier" function?

Well, it turns out I can use "google"! "Entier" is the French word for "integer" and the "Entier function" of x is the "integer part" of x- the same as the "floor" function which returns the largest integer less than or equal to x.
• Dec 27th 2011, 01:52 PM
skeeter
Re: What is the meaning of doublestruck E symbol?
Quote:

Originally Posted by HallsofIvy
Okay, don't leave us guessing- what is the "Entier" function?

the inverse of the "Departier" function ?
• Dec 27th 2011, 01:53 PM
Plato
Re: What is the meaning of doublestruck E symbol?
Quote:

Originally Posted by HallsofIvy
Okay, don't leave us guessing- what is the "Entier" function?

It is the integer function is some programming language.