  A Confirmation Rule, within blockchain networks, refers to an algorithm
implemented by network nodes that determines (either probabilistically or
deterministically) the permanence of certain blocks on the blockchain. An
example of Confirmation Rule is the Bitcoin's longest chain Confirmation Rule
where a block is confirmed (with high probability) when it has a sufficiently
long chain of successors, its siblings have notably shorter successor chains,
and network synchrony holds. In this work, we devise a Confirmation Rule for
Ethereum's consensus protocol, Gasper. Initially, our focus is on developing a
rule specifically for LMD-GHOST, the component of Gasper responsible for
ensuring dynamic availability. This is done independently of the influence of
FFG-Casper, which is designed to finalize the blocks produced by LMD-GHOST.
Subsequently, we build upon this rule to consider FFG-Casper's impact, aiming
to achieve fast block confirmations through a heuristic that balances
confirmation speed with a trade-off in safety guarantees. This refined
Confirmation Rule could potentially standardize fast block confirmation within
Gasper.
