$X_{\text{ns}}^+(N)$ is the modular curve $X_H$ for $H\le \GL_2(\widehat\Z)$ the inverse image of an extended Cartan subgroup of $\GL_2(\Z/N\Z)$ that is nonsplit at every prime dividing $N$.

**Knowl status:**

- Review status: beta
- Last edited by Asimina Hamakiotes on 2024-03-18 19:26:07

**Referred to by:**

**History:**(expand/hide all)

- 2024-03-18 19:26:07 by Asimina Hamakiotes
- 2023-07-09 09:04:08 by Andrew Sutherland
- 2022-11-06 17:04:13 by Ciaran Schembri

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