# Mistake regarding nontrivial square roots

**URL:** <https://discuss.pennylane.ai/t/mistake-regarding-nontrivial-square-roots/5424>\
**Category:** Codebook\
**Created:** [October 5, 2024, 8:52am UTC](https://discuss.pennylane.ai/t/mistake-regarding-nontrivial-square-roots/5424 "2024-10-05T08:52:17Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![Marco\_Flores](https://yyz2.discourse-cdn.com/flex012/user_avatar/discuss.pennylane.ai/marco_flores/32/2907_2.png) [@Marco\_Flores](https://discuss.pennylane.ai/u/Marco_Flores)\
**Post date:** [October 5, 2024, 8:52am UTC](https://discuss.pennylane.ai/t/mistake-regarding-nontrivial-square-roots/5424/1 "2024-10-05T08:52:17Z")

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In the section Classical Factorization of Shor’s Algorithm, in the definition of “nontrivial square root”, it should say x belongs to the set {2,…,m-2}, not {2,m-2}. Also maybe it would be nice to explain in one line why they’re called that, i.e., because 1 and -1 are always square roots.

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**Author:** ![CatalinaAlbornoz](https://yyz2.discourse-cdn.com/flex012/user_avatar/discuss.pennylane.ai/catalinaalbornoz/32/1196_2.png) [@CatalinaAlbornoz](https://discuss.pennylane.ai/u/CatalinaAlbornoz)\
**Post date:** [October 9, 2024, 2:25am UTC](https://discuss.pennylane.ai/t/mistake-regarding-nontrivial-square-roots/5424/2 "2024-10-09T02:25:19Z")

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Hi @Marco_Flores , welcome to the Forum and thanks for the suggestion!  
We’ll make sure to make this update. Thank you for helping us make the Codebook better! 🙌