{{otheruses4|⋄|<code>&lt;&gt;</code> following a type name in the Java programming language|Generics in Java#Diamond operator}} In number theory, the '''diamond operators''' 〈''d''〉 are operators acting on the space of modular forms for the congruence subgroup Γ<sub>1</sub>(''N''), given by the action of a matrix {{nowrap|({{su|p=a b|b=c δ}})}} in Γ<sub>0</sub>(''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 {{unichar|22C4|DIAMOND OPERATOR}}.<ref>{{cite web| title = Mathematical Operators – Unicode| url = https://www.unicode.org/charts/PDF/U2200.pdf| accessdate = 2013-04-22}}</ref>

== Notes == {{reflist}}

== References == * {{Citation | last1=Diamond | first1=Fred | last2=Shurman | first2=Jerry | title=A first course in modular forms | url=https://books.google.com/books?id=He6nwjGdlG4C | publisher=Springer-Verlag | location=Berlin, New York | series=Graduate Texts in Mathematics | isbn=978-0-387-23229-4 |mr=2112196 | year=2005 | volume=228}}

Category:Modular forms

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