First of all let me clear one thing, Tibet was not the part of China and fact cannot be denied that China forcefully occupied Tibet. In such instances US CIA involvement and India's support to that is legitimate cause Chinese are now on Indian border and attack on Tibet proved Chinese hostile behavior. Any nation will take measure to safeguard it's soil. Nothing wrong in that. Now you are saying that China doesn't recognize the MacMahon line hence, China can infiltrate to Indian side by claiming it is their land but, India cannot because India recognizes MacMahon line. This is the conflicting situation when you do not recognize the line then how can you expect others to respect that line? Regarding prof, there are a lot of pieces of evidence that proves Chinese incursion in Indian side. It doesn't matter if you recognize border, it doesn't matter if you recognize MacMahon line or not but if you enter into Indian side, you will not be welcomed and sent back to your place politely or forcefully. No justification can be given for incursion. Tomorrow India can claim any Chinese territorry and then petrol troops then wouldn't it be incursion?