stats: Max of three Logistic RV returns -oo

[preda]

Using git version a8eec2f

from sympy.stats import *

a = Logistic('a', 0, 1)
b = Logistic('b', 0, 1)
c = Logistic('c', 0, 1)
E(Max(a, b, c)) evaluates to -oo

(but E(Max(a, b)) evaluates to 1)

It seems to me that the E(Max(a,b,c)) result is wrong -- or am I doing something wrong?

[czgdp1807]

Current behaviour on master,

In [1]: from sympy.stats import *                                               

In [2]: a = Logistic('a', 0, 1) 
   ...: b = Logistic('b', 0, 1) 
   ...: c = Logistic('c', 0, 1)                                                 

In [3]: E(Max(a, b, c))                                                         
Out[3]: 3/2

In [4]: E(Max(a, b))                                                            
Out[4]: 1