Congress president Sonia Gandhi today invited the CPM to join the forthcoming coalition government at the Centre, adding weight to a rising chorus that the main constituent of the Left grouping should not repeat its earlier stand of ‘‘supporting from the outside.’’Sonia made the request to CPM Polit Bureau member Sitaram Yechury when he called on her this afternoon, Yechury said. In the 45-minute meeting, the two also discussed the ‘‘meaning of the mandate and the broad contours of the next government.’’ Since the mandate favoured the Congress alliance and the Left, the ‘‘government has to be left-of-Centre,’’ they agreed.As for joining the government, the CPM leader told Sonia that the decision would be taken by the Central Committee (CC) of the party at its meeting on May 16 and 17.Former Prime Minister V P Singh, in his new role as chief well-wisher and advisor of the ‘‘secular coalition,’’ also forcefully called upon the Left parties to join the government this time.He outlined reasons why. First, their participation would ‘‘send a very good signal for stability.’’ Second, it would persuade others such as Karunanidhi to join. And third, it would help the Left expand beyond their bases in West Bengal and Kerala.‘‘The communist parties will never get a better opportunity to enter the heartland and establish a rapport with the people there,’’ Singh said. When pointed out that the communists were pitted against the Congress in their strongholds and that made it difficult for them to join a Congress-led government at the Centre, Singh said, ‘‘By supporting the government, they are paying a political price anyway. Why don’t they also take the benefits of it by formulating and implementing good policies?’’ NCP, DMK may join Govt