Moduli spaces of Riemann surfaces of genus two with level structures. I
Moduli spaces of Riemann surfaces of genus two with level structures. I
The cohomology of modular varieties defined by congruence subgroups of <inline-formula content-type="math/mathml"> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="upper S p 4 left-parenthesis bold upper Z right-parenthesis"> <mml:semantics> <mml:mrow> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:msub> <mml:mi>Sp</mml:mi> <mml:mn>4</mml:mn> </mml:msub> </mml:mrow> <mml:mo stretchy="false">(</mml:mo> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mi mathvariant="bold">Z</mml:mi> </mml:mrow> </mml:mrow> <mml:mo stretchy="false">)</mml:mo> </mml:mrow> <mml:annotation encoding="application/x-tex">{\operatorname {Sp} _4}({\mathbf {Z}})</mml:annotation> …