[Help-glpk] if...then...else

[Ozgur Ican]

Hi,

i have time sets below,
 
set W; #week
set D; #day
set H; #hour

and a binary decision variable.

var delta{w in W, d in D, h in H},binary;


My question is that;
if delta[w.d,h] = 0 for a specific hour, it has to be equal to zero for the 
following 23 hours too.
That is if delta is 0 it has to be 0 for a day-time. How can i model this 
situation with "if...then...else".
Also should i put this expression into variable definition part or s.t. part 
or anywhere in the .mod file.

I think if i had only one time indice say "t" there is not any problem at all 
but in my situation time index has three sub indices

Thanks.  
 

-- 
o.ican