# Where to sequence transactions?

**URL:** <https://forum.celestia.org/t/where-to-sequence-transactions/961>\
**Category:** Settlement\
**Created:** [May 11, 2023, 1:28pm UTC](https://forum.celestia.org/t/where-to-sequence-transactions/961 "2023-05-11T13:28:28Z")\
**Posts on this page:** 1\
**Showing post:** 2

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**Author:** ![musalbas](https://forum.celestia.org/user_avatar/forum.celestia.org/musalbas/32/11_2.png) [@musalbas](https://forum.celestia.org/u/musalbas)\
**Post date:** [May 11, 2023, 11:35pm UTC](https://forum.celestia.org/t/where-to-sequence-transactions/961/2 "2023-05-11T23:35:35Z")

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I assume you’re talking about cases where you might want to do cross-contract calls between rollups, rather than simply minting and locking operations, right? What would be required on the DA layers’ side to enable X-RU atomicity?

Can you still have have X-RU atomicity implemented on the L2s/settlement rollups (eg between to L3s) or [shared sequencers](https://forum.celestia.org/t/sharing-a-sequencer-set-by-separating-execution-from-aggregation/702)? The idea of the [zk settlement proposal](https://forum.celestia.org/t/achieving-base-layer-functionality-escape-velocity-without-on-chain-smart-contracts-using-sovereign-zk-rollups/958) is that if you achieve L1 base layer functionality escape velocity, you can do anything you want on the layers above.

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