Given four unsigned numbers, find the minimum. Unsigned numbers can be compared with standard comparison operators (a < b). Use the conditional operator to make two-way min circuits, then compose a few of them to create a 4-way min circuit. You'll probably want some wire vectors for the intermediate results.
module top_module (
input [7:0] a, b, c, d,
output [7:0] min);//
wire [7:0] res1,res2;
assign res1= a<b?a:b;
assign res2= c<d?c:d;
assign min=res1<res2?res1:res2;
// assign intermediate_result1 = compare? true: false;
endmodule