bio | website | |
---|---|---|
location | Paris France | |
age | 59 | |
visits | member for | 4 years, 10 months |
seen | 14 mins ago | |
stats | profile views | 957 |
Subjects : finite maths , combinatorics, graphs , categories.
I am problem oriented and of the geometric type.
I believe the linguistic-literary side of maths should be put forward in particular as a means to fill the gap between mathematics and general culture.
Sep 24 |
awarded | Autobiographer |
Jul 21 |
comment |
Theorems true but wrong.
@djechlin : Not at all : I am saying that saying $P_1$ and $P_2 \RightArrow C_1 and C_2$ is wrong when actually each $A_i$ implies $C_i$. Also asserting " $a+b$ is less than $a'+b'$" is wrong when in fact $a$ (resp. $b$) is less than $a'$ ( resp. $b'$). |
Jul 2 |
awarded | Curious |
Feb 22 |
comment |
Less general edge reconstruction problem for simple graphs
It couls very wel be the only example... |
Feb 8 |
awarded | Nice Answer |
Feb 4 |
awarded | Revival |
Jan 24 |
awarded | Nice Answer |
Dec 24 |
comment |
A weaker concept of graph homomorphism
I have a problem with statement 2 .If you are calling the rigid definition that for homomorphism of graphs which is classical . Then you can contract any tree to K_2 (the complete graph with 2 vertices). |
Oct 29 |
awarded | Quorum |
Mar 30 |
comment |
Enumerating 0-1 finite boxes without null rays.
@Casteels : OK you are right there was a typo the 4 and the 6 where exchanged in front of the powers ^p. |
Mar 30 |
revised |
Enumerating 0-1 finite boxes without null rays.
Exchange coeffs. 6 and 4 inf front of 7^p and 3^p |
Mar 29 |
asked | Enumerating 0-1 finite boxes without null rays. |
Mar 3 |
revised |
Difficult examples for Frankl's union-closed conjecture
minor |
Mar 2 |
revised |
Difficult examples for Frankl's union-closed conjecture
Added a third point C) |
Mar 1 |
answered | Difficult examples for Frankl's union-closed conjecture |
Feb 8 |
comment |
Which finite group is not the automorphism group of some rooted finite trees
Thank you very much , there is still an aspect of "density". Do we loose kind of "half" when restricting to (FTAG) FiniteTree-Automorphism -Groups ? |
Feb 8 |
comment |
Which finite group is not the automorphism group of some rooted finite trees
How funny that my context is in fact graph isomorphism and Brendan is the first to answer this. Mysterious or funny ? |
Feb 8 |
comment |
Why is Set, and not Rel, so ubiquitous in mathematics?
Too short and too partial for an answer: I think that functions are on the technical side whereas relation are on the conceptual side. A function (partial) "is" a partition whereas a relation thought as a bipartite graph is much more complicated. A related (no pun) question is that partial functions should be used instead of function. |
Feb 8 |
asked | Which finite group is not the automorphism group of some rooted finite trees |
Jan 24 |
comment |
Galois connections
@jim It is a detail : in galois.pdf the property is symetric (not reflexive as given). |