The hemisphere function is defined as
| 
(1)
 | 
Watson (1966) defines a hemispherical function as a function  which satisfies the recurrence
 relations
| 
(2)
 | 
with
| 
(3)
 | 
 
	    
	
    
The hemisphere function is defined as
| 
(1)
 | 
Watson (1966) defines a hemispherical function as a function  which satisfies the recurrence
 relations
| 
(2)
 | 
with
| 
(3)
 | 
Weisstein, Eric W. "Hemispherical Function." From MathWorld--A Wolfram Resource. https://mathworld.wolfram.com/HemisphericalFunction.html