In number theory, the diamond operators 〈d〉 are operators acting on the space of modular forms for the congruence subgroup Γ1(N), given by the action of a matrix in Γ0(N) where δ ≈ d mod N. The diamond operators form an abelian group and commute with the Hecke operators.
Unicode In Unicode, the diamond operator is represented by the character .
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