# \#recursion

**URL:** https://community.seqera.io/tag/recursion/52.md

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## [Is there a way to check if a channel is empty and use this to determine whether to call a subworkflow?](https://community.seqera.io/t/is-there-a-way-to-check-if-a-channel-is-empty-and-use-this-to-determine-whether-to-call-a-subworkflow/658)

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**Author:** [@bskubi](https://community.seqera.io/u/bskubi)\
**Replies:** 0\
**Last updated:** [April 12, 2024, 12:54am UTC](https://community.seqera.io/t/is-there-a-way-to-check-if-a-channel-is-empty-and-use-this-to-determine-whether-to-call-a-subworkflow/658 "2024-04-12T00:54:56Z")

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I’m trying to implement a recursive workflow W. It takes as input a channel of items to process A and a channel of immediately processable items B. After calling a process on B, a subset C of members of A become processa…