1/2 strength. If you were Carthage and played Iberian cavalry, it would be 0.5 swords. If you added Numidan cavalry, it would be one sword. If you were Rome and added Equites, it would be 0.5 swords.
So what happens when a battle ends due to time constraint and the battle marker is at 0.5 defender side. It's straddling a draw and defender victory. Or any situation where it's straddling the line between draw and victory. Do you round up always? So 0.5 towards defender would be considered defender +1 and attacker +1.5 would be attacker +2?