2021-09-14 11:50:29 +0200 | asked a question | Working with unlabelled graphs Working with unlabelled graphs I'm studying certain properties of graphs but I want to work with unlabelled ones i.e. I |

2021-09-03 13:06:23 +0200 | asked a question | Permutations and transpositions Permutations and transpositions Is it possible in Sage to get the decomposition in transpositions of a permutation? |

2021-08-23 11:56:20 +0200 | asked a question | Symbolic expression of the quotient of a continued fraction Symbolic expression of the quotient of a continued fraction Hi, Is it possible to get the symbolic expression of the nu |

2021-01-07 18:21:18 +0200 | asked a question | Counting lattice path with Sage Quite newbie with Sage but I try to count very standard lattice path with steps (1,0) and (0,1) on a grin (0,0) to (m,n) for positive integers n and m. I want also put constraints like for example "not touching the main. diagonal". I can program it but maybe there are Sage libraries that can help me? Thanks for any suggestions Gianfranco |

2020-05-03 18:52:09 +0200 | asked a question | Working with rationals without simplification Hi, Is there a way to force Sage to not simplify rational fraction, I mean to not convert for example $\frac{5}{10}$ into $\frac{1}{2}$, just leave it as $\frac{5}{10}$. I could work with paires of integers instead of rational fractions but it would be a lot more convenient to use the standard operations on $\mathbb Q$ Thanks |

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2020-04-16 23:54:13 +0200 | commented question | Changing display labels of nodes on a graph Mmmh sorry for my bad english. I found finally another way to solve my problem, I think there was no solution to what I wanted to do. Thanks a lot for your time. |

2020-04-16 15:24:20 +0200 | commented question | Changing display labels of nodes on a graph The idea is the following. Let's imagine I have defined the graph : G2 = Graph([('a', 'b', 'edge label')]). Like that it is displayed with node labels 'a' et 'b'. But I want to display G2 (as it is defined) but as G3 = Graph([('Good', 'Morning')]) will be displayed |

2020-04-16 15:10:43 +0200 | commented answer | Changing display labels of nodes on a graph Oh! yes good idea, if I remove the node labels and keep only edge labels can be a way to go. Thanks |

2020-04-16 06:55:32 +0200 | received badge | ● Nice Question (source) |

2020-04-15 09:33:36 +0200 | asked a question | Changing display labels of nodes on a graph Hi, I have created a graph which is in fact a tree. Each node has a label that I gave at creation time. Now, when I plot the graph for each node this "internal" label is displayed. Is it possible to have different display labels than this "internal" label? Thanks |

2020-04-14 20:44:04 +0200 | commented question | Continued fractions with various algorithms Thanks Sebastien good to know anyway |

2020-04-14 12:55:14 +0200 | received badge | ● Student (source) |

2020-04-14 11:05:37 +0200 | asked a question | Continued fractions with various algorithms Hi, Can I find a package allowing to compute continued fractions and convergents with an algorithm different than the euclidian division ? nearest integer for example or others... Thanks |

2020-04-06 17:06:06 +0200 | commented answer | Group given by congruence relation Got it. Jesus here is how it works for me...don't ask me why... def my_congruence_group(B, N): M = MatrixSpace(Zmod(N), 2) print(M) |

2020-04-06 16:44:31 +0200 | commented answer | Group given by congruence relation Thanks. I have the 8.9 version which is recent. I have tried here: https://sagecell.sagemath.org/ and I got the same error....strange. Don't worries I don't want to waste your time I will do my investigatio and tell you if I find something...Maybe a Python 3 compatibility issue? |

2020-04-06 14:13:04 +0200 | commented answer | Group given by congruence relation Hi, Sorry to disturb you again but I have tried various ways and I get always the same error when I run the above code: Here is an extract of the fullstack just in case : ## Starts with:GAPError Traceback (most recent call last) .........continue..... ---> 23 G = my_congruence_group(B, N) 24 G.gens() # some generators for the group 25 .........continue..... ends with GAPError: Syntax error: ] expected in stream:1 [1 1] ^ Thanks for any clue |

2020-04-05 21:44:28 +0200 | commented answer | Group given by congruence relation Wonderful, thank you so much for your time and your great answer. You taught me a lot in this last two hours. I will study that with great pleasure. |

2020-04-05 20:12:27 +0200 | commented question | Group given by congruence relation Yes sorry for that, you are right, fixed. Great thanks for this point of view, gives me a step further. |

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2020-04-05 19:17:01 +0200 | commented question | Group given by congruence relation Hi, Thanks for your interest in my question . Here is the argument Essentially because $B^2 = 0$. Just to be clear, saying that $A=B \ mod(N)$ means that $A - B = N \cdot X$ where $X$ is an integral matrix 1) $I \in G$, take k=0 2) Take $A = I + mB + N\cdot X, B = I + nB + N\cdot Y\in G$ , $X,Y$ being any integer coefficients matrices. Write the product and you will see that (because $B^2=0$) we have $A \cdot B = I + (m+n)\cdot B \ mod(N)$ 3) For the inverse, you see easily that if $A = 1 + k \cdot B \mod(N)$ then $A^{-1} = 1 - k \cdot B \ mod(N)$ |

2020-04-05 14:07:20 +0200 | asked a question | Group given by congruence relation Hi, Beginner in Sage (I love it!) , I want to ask you this maybe naive question: I have a group $G$ defined by $\lbrace M \in SL_2(Z) \ | \ M = I + kB \ mod(N) \rbrace $, where $I$ is the identity, $N$ a given positive integer, $B$ is a given fixed matrix verifying $B^2 = 0$ and $k$ (not fixed) any integer in { 0,1,2,....,N-1 }. I want to explore conjugacy classes/subgroups of this group $G$ for some specific $B$ and $N$. Is this subgroup finitely generated for some $N$? subgroups of finite index? etc... Do I have a way to do that with SageMath? Remark that It is subgroup of a finitely generated group butv that do not imply that it is finitely generated $B^2 = 0$ gives that $I + kB = \Lambda^k \ with \ \Lambda = I + B$. An obvious subgroup is $ H = \lbrace \Lambda^k, \ k \in \mathbb Z \rbrace$ Any advise or web pointer would be appreciated Thanks for your help |

2020-04-05 14:07:20 +0200 | asked a question | Defining a groupe by congruences Hi, Real beginner in Sage I want to ask you this question: I have a subgroup $G = \lbrace M \in SL_2(Z) | \ M = I + kB \ mod(N) \rbrace $, where $I$ is the identity, $B$ is a given fixed matrix verifying $B^2 = 0$ and $k \in \mathbb Z /N\mathbb Z $. I want to explore subgroups of this group $G$. Do I have a way to do that with SageMath? Any advise or web pointer would be appreciated Thanks for yor help |

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