A family of cyclic quartic fields arising from modular curves
A family of cyclic quartic fields arising from modular curves
We study a family of cyclic quartic fields arising from the covering of modular curves <inline-formula content-type="math/mathml"> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="upper X 1 left-parenthesis 16 right-parenthesis right-arrow upper X 0 left-parenthesis 16 right-parenthesis"> <mml:semantics> <mml:mrow> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:msub> <mml:mi>X</mml:mi> <mml:mn>1</mml:mn> </mml:msub> </mml:mrow> <mml:mo stretchy="false">(</mml:mo> <mml:mn>16</mml:mn> <mml:mo stretchy="false">)</mml:mo> <mml:mo stretchy="false">→<!-- → --></mml:mo> …