Eigenform Product Identities For Hilbert Modular Forms


Abstract in English

We prove that amongst all real quadratic fields and all spaces of Hilbert modular forms of full level and of weight $2$ or greater, the product of two Hecke eigenforms is not a Hecke eigenform except for finitely many real quadratic fields and finitely many weights. We show that for $mathbb Q(sqrt 5)$ there are exactly two such identities.

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