Concepts
Sponsors and gas
Someone pays for the whole transaction. The wallets pay nothing.
What a sponsor does
The sponsor sends the type-4 transaction and pays its gas. It cannot change what the arms do, and it gains no control over them. It can be any funded address, including one of the arms.
Measured numbers
| Run | Result |
|---|---|
| 8 arms, one type-4 transaction, local node, mock curve | 951,810 gas in total, about 119,000 per arm |
| Arm nonce and calls | Each arm bumps one storage slot and runs its calls |
| Wallets' gas balance | 0 ETH needed, 0 ETH taken |
The per-arm figure includes the mock curve minting a token, so a real curve will differ. This is not a promise of savings: eight separate transactions would cost similar gas in total. The point is one block and no gas balances.
Who can sponsor
Anyone. A group can rotate sponsors, or one person can run all the arms and sponsor with a separate wallet. The sponsor address never appears as the buyer.
Fees
There is no protocol fee in this version. A tip for sponsors could be added later as a separate contract.