Hi I have some questions about grin usage as a currency.
Is it possible to make off-chain transactions, just by not posting the finalized transaction to the node network, but giving the finalized transaction to the receiver who can spend it again off-chain or on-chain?
If that is possible, anyone in the off-chain-chain could do a double-spend. But that would be just be a problem, similar to other classic payment systems. And the classic solution, with a classic contract could be used for example.
Would it be possible to have side-chains or side-tangles?