Hi People.
I have a   data set  of numbers  which can be described as follows : 
{{{a,b,c,d},{g,h,k,l}},{{a,b,c,d},{g,h,k,l}},{{a,b,c,d},{g,h,k,l}},{{a,b,c,d},{g,h,k,l}},{{a,b,c,d},{g,h,k,l}}....}
And I'm trying to use the function: 
f3[{{a_, b_, c_, d_}, {g_, h_, k_, l_}}] := ( [(l - d)] + 0.01)/((Max[h, d]) - (Min[k, d]) + 0.01)
The thing is that I like the function to be used only in the  case  when l and d  are not equal.
I tried to use   /;  but the messages the mathematica issued were not clear enough for me .