FUNCTION :  ETA[vetainf] -  order at infinity of eta-quotient

CALLING SEQUENCE :  vetainf()                                          
                    vetainf(epterm)                                          

PARAMETERS :
   epterm = c*eta(t[1]*tau)^r[1]* ... *eta(t[s]*tau)^r[s]    
           ie. an eta-quotient times a constant. 

GLOBAL VARIABLES : 

SYNOPSIS :   
   Returns the v[oo](epterm).
   
EXAMPLES :   

DISCUSSION :

SEE ALSO :