/* EU_B.G: procedure to return (deterministic,publicly observable) component of
           player b's expected utility function, which depends on player b's 
	   belief of the probability that player a will confess, p_a. 
	   Private information part is an additive extreme value distributed 
	   shock known to prisoner b but not to prisoner a. Symmetrically, 
           prisoner b does not know prisoner a's private type, and so from the
	   standpoint of prisoner b, prisoner a decision to confess is probabilistic,
	   a result of a's private information which prisoner b does not observe.

	  Inputs: 

	  d_a: decision of prisoner a, 1 = confess, 0= don't confess
	  d_b: decision of prisoner b, 1 = confess, 0= don't confess
	  x_b: prisoner b's observable type, assumed to be restricted to [0,1]
	  p_a: prisoner b's belief of the probability that prisoner a will
	       confess, obviously restricted to the [0,1] interval

	  John Rust, University of Maryland, November, 2005 */

   proc (1)=eu_b(d_b,x_b,p_a);


       if ((d_b == 1));

            retp (p_a*u_b(1,1,x_b)+(1-p_a)*u_b(0,1,x_b));

       else;

            retp (p_a*u_b(1,0,x_b)+(1-p_a)*u_b(0,0,x_b));

       endif;

   endp;