Is it possible to have the following scenario?
- Account A has 20 ether, account B has 20 ether
- In transaction 1. Account A sends 25 ether to account B
- In transaction 2. Account B sends 10 ether to account A
- Both transactions are submitted almost at the same time so they will be a part of the same block
After the block is mined the net effect is account A sends 15 ether to account B. So there is enough ether in both accounts to satisfy the account balances.
But does Ethereum infrastructure allows for such operations?