Ask Your Question

Tintin1's profile - activity

2024-02-13 22:02:29 +0100 asked a question Auslander-Reiten Quiver - knitting

Ausland-Reiten Quiver - knitting Given a quiver representation A3= DiGraph({1:{2:['a']}, 2:{3:['b']}}) or A4= DiGr

2023-09-11 01:02:11 +0100 edited question tetrahedron with each face differently colored?

tetrahedron with each face differently colored? I am running the code G = tetrahedron(color='blue') G.show(aspect_rat

2023-09-11 00:32:52 +0100 asked a question tetrahedron with each face differently colored?

tetrahedron with each face differently colored? I am running the code G = tetrahedron(color='blue') G.show(aspect_rat

2023-01-19 00:10:13 +0100 received badge  Popular Question (source)
2023-01-18 14:44:51 +0100 asked a question quasi-affine subvarieties

quasi-affine subvarieties I would like to set up a quasi-affine variety in $\mathbb{A}^2$ (over a field of characteristi

2022-11-19 15:02:27 +0100 asked a question implicit_plot doubled straight line

implicit_plot doubled straight line How come this plotted straight line is doubled? x, y = var('x,y') show(implicit_plo

2022-10-22 11:20:08 +0100 edited question plot the the intersection of two surfaces in 3d, use of a special colour for the intersection

plot the the intersection of two surfaces in 3d, use of a special colour for the intersection Is it possible to colour t

2022-10-22 11:19:22 +0100 edited question plot the the intersection of two surfaces in 3d, use of a special colour for the intersection

plot the the intersection of two surfaces in 3d, use of a special colour for the intersection Is it possible to colour t

2022-10-22 11:18:45 +0100 edited question plot the the intersection of two surfaces in 3d, use of a special colour for the intersection

plot the the intersection of two surfaces in 3d, use of a special colour for the intersection Is it possible to colour t

2022-10-22 11:18:22 +0100 asked a question plot the the intersection of two surfaces in 3d, use of a special colour for the intersection

plot the the intersection of two surfaces in 3d, use of a special colour for the intersection Is it possible to colour t

2022-10-14 20:42:07 +0100 edited question Draw the real part of a hypersurface in a real 3d-plot in the affine 3-space over C

Draw the real part of a hyperspace in a real 3d-plot in the affine 3-space over C Is it possible to 3d-plot the (rationa

2022-10-14 20:42:04 +0100 edited question Draw the real part of a hypersurface in a real 3d-plot in the affine 3-space over C

Draw the real part of a hyperspace in a real 3d-plot in the affine 3-space over C Is it possible to 3d-plot the (rationa

2022-10-14 20:41:42 +0100 edited question Draw the real part of a hypersurface in a real 3d-plot in the affine 3-space over C

Draw the real part of a hyperspace in a real 3d-plot in the affine 3-space over C Is it possible to 3d-plot the (rationa

2022-10-14 20:40:56 +0100 asked a question Draw the real part of a hypersurface in a real 3d-plot in the affine 3-space over C

Draw the real part of a hyperspace in a real 3d-plot in the affine 3-space over C Is it possible to 3d-plot the (rationa

2022-05-08 21:55:15 +0100 commented question type error when calculating a limit

yes, I imported sympy. you found the bug. Now it works, after removing the import of sympy. How do I avoid the conflicti

2022-05-08 21:54:47 +0100 commented question type error when calculating a limit

yes, I imported sympy. you found the bug. Now it works, after removing the import of sympy. How do I avoid the conflicti

2022-05-08 21:53:55 +0100 commented question type error when calculating a limit

yes, I imported sympy. you found the bug. Now it works.

2022-05-08 18:31:13 +0100 asked a question type error when calculating a limit

type error when calculating a limit I am trying to calculate a limit: print(limit(1/x,x=0)) Why do I get the followin

2021-01-15 10:35:52 +0100 commented question Solve matrix equation in sympy

Is there possibly a completely different approach outside of sympy to calculate v=0?

2021-01-13 22:11:37 +0100 commented question Solve matrix equation in sympy

I am not sure how to assure that Q has full rank.

2021-01-13 21:38:17 +0100 asked a question Solve matrix equation in sympy

How can I solve Q*v=0 for v in matrix terms (Q is a matrix, v is a vector). v should be a zero vector. The matrix Q is supposed to be invertible and full rank.

from sympy.solvers import solve
from sympy import symbols
from sympy import MatrixSymbol
n=symbols('n')
v = MatrixSymbol('v', n, 1)
Q = MatrixSymbol('Q', n, n)
eq=Q*v
solve(eq,v)

Please help, thanks.

2021-01-02 17:25:16 +0100 answered a question restricting a NumberField to the reals for the calculation of a Galois group

The question might be addressed by considering a specific subfield:

 x=QQbar(7**(1/8))
 L.<x>=NumberField(x.minpoly())
 Ls=L.subfields(degree=2)           
 print(Ls)
 G=Ls[0][0].galois_group(names='x')
 print(G.list())

In this case, the subfield which is real is of degree 2, seen as a vector space. The number field can be restricted to the reals by considering the appropriate subfield which is a proper subset of the reals. The output of the above code is

[
(Number Field in x0 with defining polynomial x^2 - 7, Ring morphism:
  From: Number Field in x0 with defining polynomial x^2 - 7
  To:   Number Field in x with defining polynomial x^8 - 7
  Defn: x0 |--> -x^4, None)
]
[(), (1,2)]
2021-01-02 14:18:14 +0100 asked a question restricting a NumberField to the reals for the calculation of a Galois group

I am trying to calculate a Galois Group. I have the following code

x=QQbar(7**(1/8))
L.<x>=NumberField(x.minpoly())
G=L.galois_group(names='x')
print(G)

The output is

Galois group of Galois closure in x of Number Field in x with defining polynomial x^8 - 7

I would like to restrict the number field L to the reals. My number field should be non-complex and contain the real root of the minimum polynomial only. How do I acchieve that in my code?

Thanks

2021-01-02 14:16:47 +0100 asked a question Number field from minimal polynomial restricted to reals, adjoining only a real root to Q

I am trying to calculate a Galois Group. I have the following code

x=QQbar(7**(1/8))
L.<x>=NumberField(x.minpoly())
G=L.galois_group(names='x')
print(G)

The output is

Galois group of Galois closure in x of Number Field in x with defining polynomial x^8 - 7

I would like to restrict the number field L to the reals. My number field should be non-complex and include only the real root of the minimum polynomial? How do I acchieve that in my code?

Thanks

2019-11-05 13:33:55 +0100 commented answer linear algebra derivative expressions

You are right, but I am trying to create a procedure for much more complicated algebraic expressions.

2019-11-03 14:09:39 +0100 received badge  Student (source)
2019-11-03 13:47:12 +0100 received badge  Editor (source)
2019-11-03 13:46:47 +0100 asked a question linear algebra derivative expressions

How do I differentiate $\mathbf{y}=\mathbf{A}\mathbf{x}$ symbolically in sagemath with respect to the vector $\mathbf{x}$? The result is obviously $\mathbf{A}$. Similarly, I would like to be able to calculate the derivative of the quadratic form $\alpha=\mathbf{x}'\mathbf{A}\mathbf{x}$. I would need these calculations in a more complex setting.

I started off with sympy as follows

from sympy import *
n=7 
A = MatrixSymbol('A', n, n)
x = MatrixSymbol('x', n, 1)

Or is there a different library from sympy available for such a problem?

2019-10-14 15:32:41 +0100 asked a question Schwarz-Christoffel transformations

I would like to visualize the Schwarz-Christoffel transformations. Do you have an idea how to implement those? For example a polygon (as a domain) in the complex plane and subsequently also a map (decomposed into several steps) into the upper half-plane of the complex plane should be drawn. I am not quite sure how to do this. The formulas for these transformations are well-known.