public String isEmpty(DataFactory factory, Context c, HashMap map) {
		IVPBoolean isEmpty = factory.createIVPBoolean();
		boolean test = true;
		int col = c.getInt(nColID);
		int lin = c.getInt(nLinID);
		for (int i = 0; i < lin; i++) {
			for (int j = 0; j < col; j++) {
				if (matrixRepresentation[i][j] != IVPValue.NULL) {
					test = false;
					break;
				}
			}
		}
		c.addBoolean(isEmpty.getUniqueID(), new Boolean(test));
		return isEmpty.getUniqueID();
	}