Negative Doubles

Board 6
East Deals
E-W Vul
♠A 10 6 3 2
♥10 5 4
♦Q 10 7
♣7 3
♠9 7
♥A 9 3 2
♦A 9 5
♣K 10 9 2
N
WE
S
♠J
♥K J 8 6
♦K J 8 4
♣Q J 6 4
♠K Q 8 5 4
♥Q 7
♦6 3 2
♣A 8 5
WestNorthEastSouth
  1♦11♠2
Dbl34♠4All pass 
  1. E opens 1♦
  2. S overcalls 1S
  3. Negative double from W showing ♥
  4. Does N Compete with ♠? Some will....
4♠ by South