@Override
	public boolean equals(Object obj) {
		if (this == obj)
			return true;
		if (obj == null)
			return false;
		if (getClass() != obj.getClass())
			return false;
		BinaryOperatorFormula other = (BinaryOperatorFormula) obj;
		if (leftArgument == null) {
			if (other.leftArgument != null)
				return false;
		} else if (!leftArgument.equals(other.leftArgument))
			return false;
		if (rightArgument == null) {
			if (other.rightArgument != null)
				return false;
		} else if (!rightArgument.equals(other.rightArgument))
			return false;
		return true;
	}