There are a number of functions in mathematics commonly denoted with a Greek letter lambda. Examples of one-variable functions denoted 
with a lower case lambda include the Carmichael
functions, Dirichlet lambda function,
elliptic lambda function, and Liouville
function. Examples of one-variable functions denoted 
with an upper case lambda 
include the Mangoldt
function and the lambda function defined by Jahnke and Emden (1945).
The triangle function, illustrated above, is commonly denoted 
.
The lambda function defined by Jahnke and Emden (1945) is
 |
(1)
|
where 
is a Bessel function of the first kind
and 
is the gamma function. 
, and taking 
gives the special case
 |
(2)
|
where 
is the jinc function.
A two-variable lambda function is defined as
 |
(3)
|
where 
is the gamma function (McLachlan et al. 1950,
p. 9; Prudnikov et al. 1990, p. 798; Gradshteyn and Ryzhik 2000,
p. 1109).
,
, 
, 
, 
." §9.64 in