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Register a new userEigenvalue of Fricke involution on newforms of level 4 and of trivial character
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Authors
Yichao Zhang
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In this note, we consider the newforms of integral weight, level 4 and of trivial character, and prove that all of them are actually level 1 forms of some non-Dirichlet character. As a byproduct, we can prove that all of them are eigenfunctions of the Fricke involution with eigenvalue -1.
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