Why does Ouroboros Praos introduce slot leader sets?
*Slot leader sets*, also known as *competitive slots* were not part of the original [Ourobors paper](https://eprint.iacr.org/2016/889.pdf), however [Ouroboros Praos](https://eprint.iacr.org/2017/573.pdf) introduces *slot leader sets*, aka a single slot can be assigned to multiple stake pools and then multiple pools compete for their respective block to be included in a chain, which is determined by a next slot leader(s) who decide which parent block they use for their freshly produced block.
This reduces transaction finality in Cardano blockchain, however when reviewing the Ourobors Praos paper, one will discover that there is no justification as to why slot leader sets would be beneficial for the protocol, namely in section 3 The Static Stake Protocol, following is said:
>We first consider the static stake case, where the stake distribution is fixed throughout protocol execution. The general structure of the protocol in the semi-synchronous model is similar to that of (synchronous) Ouroboros \[KRDO17\] but introduces several fundamental modifications to the leader selection process: not all slots will be attributed a slot leader, **some slots might have multiple slot leaders**, and slot leaders’ identities remain unknown until they act. **The first modification is used to deal with delays in the semi-synchronous network as the empty slots**—where no block is generated—assist the honest parties to synchronize. **The last modification is used to deal with adaptive corruptions**, as it prevents the adversary from learning the slot leaders’ identity ahead of time and using this knowledge to strategically corrupt coalitions of parties with large (future) influence.
Later in section 3.3 Oblivious Leader Selection and F(INIT) you can find following:
>As in (synchronous) Ouroboros, for each 0 < j ≤ R, a slot leader Ej is a stakeholder who is elected to generate a block at slj . However, our leader selection process differs from Ouroboros \[KRDO17\] in three points: (1...