Take the 2-minute tour ×
Mathematics Stack Exchange is a question and answer site for people studying math at any level and professionals in related fields. It's 100% free, no registration required.

I have morphisms:

$$ f : A \to B \\ g : B \to C $$

The composition is:

$$ g \circ f : A \to C $$

In the function $(g \circ f)$ we call $A$ the domain and $C$ the codomain (or range).

I'm working in Haskell code, and in my application the type we pass through $(B)$ is particularly important. Does this intermediate value have a standard name?

share|improve this question
1  
Why is "the range of $f$" or "the domain of $g$" not what you want? –  mt_ Dec 18 '12 at 8:34
    
@mt_ I was hoping there was a standard one-word thing I could call the type in code (e.g. "pseudodomain") to make the code easier to read. –  Mike Izbicki Dec 18 '12 at 8:36
5  
One usually says that the morphism factors through B. Perhaps this could inspire a suitable name. –  Adeel Dec 18 '12 at 8:53
4  
Of course the reason that B has no name is that there is no B! If all you have is the "result" of the composition there is no way to know what B was or what f and g were individually. If on the other hand you do have f and g you also have B. –  Omar Antolín-Camarena Dec 18 '12 at 14:51
1  
@Adeel Thanks. I'm calling it the factordomain, and that seems pretty reasonable. –  Mike Izbicki Dec 18 '12 at 20:16

1 Answer 1

Based on Adeel's comment above, I've been calling $B$ the "factor domain."

share|improve this answer

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.