ASKSAGE: Sage Q&A Forum - RSS feedhttps://ask.sagemath.org/questions/Q&A Forum for SageenCopyright Sage, 2010. Some rights reserved under creative commons license.Thu, 17 Jun 2021 17:48:15 +0200Computing the ideal below in a cyclotomic fieldhttps://ask.sagemath.org/question/57601/computing-the-ideal-below-in-a-cyclotomic-field/ I have a cyclotomic field L, and I define K as a decomposition field for an ideal (non prime) I of OL. ( I made the decomposition field function ). I know that K is a subfield of L, but it just considers it as an extension of Q. I would like to calculate the intersection of I and OK or of I and K, which is supposed to be the ideal below I in K. I've tried the "intersection" function, but it doesn't work because they don't consider OK as an L-ideal. I've also tried the ideal_below function, but it tells me that a NumberFieldFractionalIdeal does not have the method.
Thank you for your help.Thu, 17 Jun 2021 10:51:01 +0200https://ask.sagemath.org/question/57601/computing-the-ideal-below-in-a-cyclotomic-field/Comment by FrédéricC for <p>I have a cyclotomic field L, and I define K as a decomposition field for an ideal (non prime) I of OL. ( I made the decomposition field function ). I know that K is a subfield of L, but it just considers it as an extension of Q. I would like to calculate the intersection of I and OK or of I and K, which is supposed to be the ideal below I in K. I've tried the "intersection" function, but it doesn't work because they don't consider OK as an L-ideal. I've also tried the ideal_below function, but it tells me that a NumberFieldFractionalIdeal does not have the method.</p>
<p>Thank you for your help.</p>
https://ask.sagemath.org/question/57601/computing-the-ideal-below-in-a-cyclotomic-field/?comment=57603#post-id-57603Please give us copy-pastable code displaying a minimal example.Thu, 17 Jun 2021 17:48:15 +0200https://ask.sagemath.org/question/57601/computing-the-ideal-below-in-a-cyclotomic-field/?comment=57603#post-id-57603