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2021-04-16 19:29:20 +0200 | answered a question | matrix_plot not returning any outputs in subroutines The reason is the following: the notebook and command line interface, when they are evaluating input, at the end they al |
2021-04-16 19:17:37 +0200 | edited answer | Cannot evaluate symbolic expression to a numerical value From the documentation of roots: Return roots of self that can be found exactly, possibly with multiplicities. Not a |
2021-04-16 19:16:59 +0200 | answered a question | Cannot evaluate symbolic expression to a numerical value From the documentation of roots: Return roots of self that can be found exactly, possibly with multiplicities. Not a |
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2021-04-13 10:53:41 +0200 | answered a question | possible bug: kernel of ring homomorphism This was a bug which has been fixed in the meantime. |
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2021-04-11 13:23:52 +0200 | answered a question | inequalities in sagemath I don't know what solve is doing (with inequalities/assumptions), but here your system of polynomial equations has finit |
2021-04-08 08:32:15 +0200 | commented question | "Ratio" of two elements in a ring You can use the normal basis associated to a GrÃ¶bner basis. Please add an example of R. |
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2021-04-01 09:04:10 +0200 | commented question | Why am I getting a type error when I attempt to take the projective closure of this intersection? The code seems to work as given over here. Have you tried it in the latest version of Sage? |
2021-03-24 16:34:53 +0200 | answered a question | large finite fields with modulus='primitive' do not satisfy equality You instruct SageMath twice to create a finite field with $2^{n}$ elements with a primitive modulus. Effectively, each t |
2021-03-23 07:35:53 +0200 | answered a question | matrix over symbolic ring to matrix over finite field In the code you added, the ideal ends up in a univariate polynomial ring over a multivariate polynomial ring, rather tha |
2021-03-22 11:59:22 +0200 | commented question | matrix over symbolic ring to matrix over finite field Yes, please add a complete block of code that ends in an error. So far, it is not clear how e.g. x_1_2_1 ends up in the |
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2021-03-13 20:40:39 +0200 | edited answer | Fraction must have unit denominator when studying Elliptic Curve over complex field? When you write QQbar['a'] you get a polynomial ring over QQbar with variable named a, so an elliptic curve over QQbar['a |
2021-03-13 20:36:57 +0200 | answered a question | Fraction must have unit denominator when studying Elliptic Curve over complex field? When you write QQbar['a'] you get a polynomial ring over QQbar with variable named a, so an elliptic curve over QQbar['a |
2021-03-08 22:42:55 +0200 | commented question | Customizing sage objects latex behaviour For vectors: I don't see a non-hacky way to do it currently, but looking at the implementation of _latex_ with v._latex_ |
2021-03-03 17:13:21 +0200 | commented question | Fit model data Up to a small numerical difference the results are the same, because for the second set of parameters $a^b \approx 2^{1/ |
2021-02-28 08:40:43 +0200 | commented question | Ask Sagemath has a new home ! Some dates (e.g. on the front page) display as 0 years ago, which is accurate but not very precise. |
2021-02-25 20:32:59 +0200 | commented question | Evaluate constants in symbolic expression? Using https://ask.sagemath.org/question/460... you can do |
2021-02-23 09:52:31 +0200 | commented question | alternative to jupyter notebook? At least as a workaround you can save and load intermediate results (see the examples there). |
2021-02-21 11:39:56 +0200 | answered a question | Turning a closed subscheme into a point You can use the rational_points method: By the way, also for points defined over other fields: |
2021-02-09 15:28:59 +0200 | commented question | possible bug: kernel of ring homomorphism Now reported on trac. |
2021-02-03 23:21:30 +0200 | commented question | What is the .sigma() function for an elliptic curve's formal group? I don't know the answer, but you can view the implementation by entering the following: Perhaps something will look familiar. |
2021-02-03 19:06:08 +0200 | commented question | Sage crash when computing variety for an ideal with many variables Please fix your code so that it works when pasted into https://sagecell.sagemath.org/. Then try |
2021-02-03 19:01:30 +0200 | answered a question | How to print positive integers that divides a number without a remainder? |
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2021-02-02 14:15:17 +0200 | commented question | Sage crash when computing variety for an ideal with many variables Please make your code self-contained so that it works in a fresh session (e.g. |
2021-02-01 09:45:51 +0200 | commented answer | subs in vector field Just curious: Couldn't OP's code be made to work? The fact that |
2021-01-22 12:35:43 +0200 | commented question | when I must declare f= or f(x,y)= ? The problem is with |
2021-01-20 13:38:07 +0200 | answered a question | How to index all elements of a finite field? Using the more standard indexing: |
2021-01-20 13:32:46 +0200 | commented question | How to index all elements of a finite field? What is the logic behind this indexing? The more usual way is to associate $f(x)$ to $f(p) \in \mathbb{N}$, so $x^2$ corresponds to $9$ and $x+1$ corresponds to $4$. |
2021-01-19 19:36:29 +0200 | answered a question | Solving symbolic equations to IntegerModRing(26) You can define a polynomial ring over $\mathbb{Z}/26\mathbb{Z}$ with an ideal in it generated by (the left-hand sides of) your equations, and calculate a Groebner basis of it with respect to a lexicographic monomial ordering. This will "triangularize" the system of equations, and if you are lucky you can solve it by successive substitutions. Here is the setup: I replaced $i$ by $-5$ because it will lead to a solution; the other option, i.e. $5$, doesn't. This can be viewed as a list of equations (set equal to zero). Each of these equations can be solved by putting its first term to the other side (so only The system of equations with $i$ replaced by $5$ is unsolvable because the Groebner basis contains the constant $2$, or, if you prefer: because |
2021-01-17 16:15:47 +0200 | answered a question | Determine Two quadratic form is integer congruence (rational equivalent)? The method This calls the PARI function qfisom, which implements an algorithm of Plesken and Souvignier. |
2021-01-04 16:13:59 +0200 | answered a question | inverse image under ring homomorphism Thanks for reporting this bug; it is now tracked at trac ticket #31178. Edit: It was fixed on the same day, and the bugfix has since been merged into SageMath. The first beta that includes this fix is 9.3.beta6, which will be released soon. |
2020-12-23 13:47:24 +0200 | answered a question | How i can create s-box 4 by 4 There is a list of S-Boxes used in cryptographic schemes in the reference manual (including 4x4 ones). The first one is called Elephant, and can be accessed and used like this: You can also create them yourself: It is explained on the page S-Boxes and Their Algebraic Representations. |
2020-12-22 22:14:10 +0200 | answered a question | Matrix-scalar and vector-scalar operations This kind of coercion is documented:
Symbolic expressions can be coerced to symbolic matrices of a fixed size: It is because there is a canonical map, mapping $1$ to the identity matrix, which is a morphism of algebras with basis. Symbolic expressions cannot be coerced to vectors of a fixed size: It is because there is no canonical map which is a morphism of modules with basis. Of course there exist morphisms, like the $1 \mapsto (1,1,1)$ you suggest, but that is no better than $1 \mapsto (1,0,0)$ or $1 \mapsto (0,0,1)$. There is no obvious natural choice, so there is no coercion. |
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