# Thread: What is the meaning of doublestruck E symbol?

1. ## 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).

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?

2. ## Re: What is the meaning of doublestruck E symbol?

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).

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.
$\displaystyle \mathbb{ABCDEF}\cdots$

3. ## 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.

4. ## 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.

5. ## 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.

6. ## Re: What is the meaning of doublestruck E symbol?

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

7. ## Re: What is the meaning of doublestruck E symbol?

Originally Posted by HallsofIvy
Okay, don't leave us guessing- what is the "Entier" function?
It is the integer function is some programming language.