# Exact Sequences - functions on longright arrows

#### Peter

##### Well-known member
MHB Site Helper
In exact sequences, a convenient notation is to have a function symbol like
$\psi$
on a longrightarrow.

I have given an example of this in the attachment so it is clear what notation I am requesting help with - see attachment "Exact Sequences - Latex Question"

I have also provided an attachment showing the start of Section 10.5 (Exact Sequences) of Dummit and Foote where there are a number of examples of the terminology I am hoping to use in Latex encoded postings.

If someone can help me with this problem I would be most grateful

Peter

[This has also been posted on MHF]

#### Opalg

##### MHB Oldtimer
Staff member
\stackrel{\psi}{\longrightarrow}: $\stackrel{\psi}{\longrightarrow}$

#### Peter

##### Well-known member
MHB Site Helper
\stackrel{\psi}{\longrightarrow}: $\stackrel{\psi}{\longrightarrow}$
Also, \xrightarrow[\text{below arrow}]{\text{above arrow}} gives $\xrightarrow[\text{below arrow}]{\text{above arrow}}$, and \overset{\psi}{\longrightarrow} gives $\overset{\psi}{\longrightarrow}$. The latter command is provided by the amsmath package, and, unlike \stackrel, can be used on ordinary symbols and binary operators and not only relations. See also this thread.