Product of $e in A/J(A)$ with an element of $J(A)$ [GAP]
$begingroup$
I have defined a matrix algebra over the rationals, calculated its radical, and took the semi-simple coefficient using h:=NaturalHomomorphismByIdeal and $ImagesSource(h)$. Afterwards, I calculated the idempotents of the semisimple coefficient using 'CentralIdempotentsOfAlgebra'. I also found the generators of the radical $J(A)$, as well as its square $J(A)^2$.
Now, I am trying to use the information to calculate the quiver of the original algebra. For that, I need to calculate the product of the idempotents $e_i$ and $e_j$ with the Jacobson radical, with arrows existing from $e_i$ to $e_j$ iff $q:=e_iJ(A)e_j/e_iJ(A)^2e_jneq 0$. And the number of arrows is the dimension of the vector space $q$. I cannot seem to calculate the dimension using the standard $Dimension$ function, or a basis using the standard $Basis$ function, since I have $e_i$ and $e_j$ as elements of the semi-simple coefficient, given as a linear combination of the generators $[v.1,cdots,v.6]$, while the generators of $J(A)$ are matrices.
A second problem is that $IsAlgebraWithOne(sscoef)$ returns $False$, while $One(sscoef)$ returns $v.1$, and $IsAlgebra(sscoef)$ returns $True$.
What am I missing?
Here is the code:
Constructing a non-commutative polynomial algebra
LoadPackage("GBNP");
A:=FreeAssociativeAlgebraWithOne(Rationals,"a","b","c");;
a:=A.a;;b:=A.b;;c:=A.c;;z:=Zero(A);;e:=One(A);;
relation1:=a^2-e;;relation2:=b^2-e;;relation3:=c^2-e;;relation4:=ab+bc+ca+e;; relation5:=ac+cb+ba+e;;
relationlist:=GP2NPList([relation1,relation2,relation3,relation4,relation5]);;
grobnerbasis:=SGrobner(relationlist);;
qabasis:=BaseQA(grobnerbasis,3,0);;
qamatrices:=MatricesQA(3,qabasis,grobnerbasis);;
Transform it into a matrix algebra, so that we can use the standard GAP-functions to calculate the radical.
matrixalgebra:=AlgebraWithOne(Rationals, qamatrices);;
jacobsonradical:=RadicalOfAlgebra(matrixalgebra);;
h:=NaturalHomomorphismByIdeal(matrixalgebra,jacobsonradical);;
sscoef:=ImagesSource(h);;
idempotents:=CentralIdempotentsOfAlgebra(sscoef);;
gensofsscoef:=GeneratorsOfAlgebra(sscoef);;
Caluclating the generators' respective commutators
commutatorlist:=;;
for i in [1..Length(gensofsscoef)] do
for j in [i..Length(gensofsscoef)] do
Add(commutatorlist, gensofsscoef[i]*gensofsscoef[j] - gensofsscoef[j]*gensofsscoef[i]);
od;
od;
commutatorlist;
We have that it is commutative.Now we calculate the arrows. e_iJ(A)e_j/e_iJ(A)^2e_j
gensofjacobsonradical:=GeneratorsOfAlgebra(jacobsonradical);;
idemstimesjacobson:=;
for e_i in [1..Length(idempotents)] do
Add(idemstimesjacobson,);
for e_j in [1..Length(idempotents)] do
Add(idemstimesjacobson[e_i],);
for genofjacobson in gensofjacobsonradical do
Add(idemstimesjacobson[e_i][e_j], idempotents[e_i]genofjacobsonidempotents[e_j]);
od;
od;
od;
Here, we construct a Length(idempotents)xLength(gensofjacobsonradical)xLength(idempotents) array.
jacobsonradicalsquared:=;
for genofjacobson1 in gensofjacobsonradical do
for genofjacobson2 in gensofjacobsonradical do
Add(jacobsonradicalsquared, genofjacobson1*genofjacobson2);
od;
od;
idemstimesjacobsonsquared:=;
for e_i in [1..Length(idempotents)] do
Add(idemstimesjacobsonsquared,);
for e_j in [1..Length(idempotents)] do
Add(idemstimesjacobsonsquared[e_i],);
for genofjacobson in jacobsonradicalsquared do
Add(idemstimesjacobsonsquared[e_i][e_j], idempotents[e_i]genofjacobsonidempotents[e_j]);
od;
od;
od;
With this, we have e_iJ(A)e_j and e_iJ(A)^2e_j. Need to save the dimension of the quotient as the number of vertices.
vertices:=;
for e_i in [1..Length(idempotents)] do
Add(vertices, );
for e_j in [1..Length(idempotents)] do
numerator:=Ideal(matrixalgebra,idemstimesjacobson[e_i][e_j]);
denominator:=Ideal(matrixalgebra, idemstimesjacobsonsquared[e_i][e_j]);
if Dimension(numerator/denominator) > 0 then
Add(vertices[e_i], [e_i, e_j, Dimension(numerator/denominator)]);
fi;
od;
od;
vertices;
The end-result should be the quiver of $A$. However, the $Dimension$ function returns the following error:
Error, usage: TwoSidedIdeal( , [, "basis"] ) at /proc/cygdrive/C/gap-4.9.3/lib/ideal.gi:42 called from
Ideal( matrixalgebra, idemstimesjacobson[e_i][e_j] ) at stdin:152 called from
( )
called from read-eval loop at stdin:158
linear-algebra abstract-algebra gap
$endgroup$
|
show 1 more comment
$begingroup$
I have defined a matrix algebra over the rationals, calculated its radical, and took the semi-simple coefficient using h:=NaturalHomomorphismByIdeal and $ImagesSource(h)$. Afterwards, I calculated the idempotents of the semisimple coefficient using 'CentralIdempotentsOfAlgebra'. I also found the generators of the radical $J(A)$, as well as its square $J(A)^2$.
Now, I am trying to use the information to calculate the quiver of the original algebra. For that, I need to calculate the product of the idempotents $e_i$ and $e_j$ with the Jacobson radical, with arrows existing from $e_i$ to $e_j$ iff $q:=e_iJ(A)e_j/e_iJ(A)^2e_jneq 0$. And the number of arrows is the dimension of the vector space $q$. I cannot seem to calculate the dimension using the standard $Dimension$ function, or a basis using the standard $Basis$ function, since I have $e_i$ and $e_j$ as elements of the semi-simple coefficient, given as a linear combination of the generators $[v.1,cdots,v.6]$, while the generators of $J(A)$ are matrices.
A second problem is that $IsAlgebraWithOne(sscoef)$ returns $False$, while $One(sscoef)$ returns $v.1$, and $IsAlgebra(sscoef)$ returns $True$.
What am I missing?
Here is the code:
Constructing a non-commutative polynomial algebra
LoadPackage("GBNP");
A:=FreeAssociativeAlgebraWithOne(Rationals,"a","b","c");;
a:=A.a;;b:=A.b;;c:=A.c;;z:=Zero(A);;e:=One(A);;
relation1:=a^2-e;;relation2:=b^2-e;;relation3:=c^2-e;;relation4:=ab+bc+ca+e;; relation5:=ac+cb+ba+e;;
relationlist:=GP2NPList([relation1,relation2,relation3,relation4,relation5]);;
grobnerbasis:=SGrobner(relationlist);;
qabasis:=BaseQA(grobnerbasis,3,0);;
qamatrices:=MatricesQA(3,qabasis,grobnerbasis);;
Transform it into a matrix algebra, so that we can use the standard GAP-functions to calculate the radical.
matrixalgebra:=AlgebraWithOne(Rationals, qamatrices);;
jacobsonradical:=RadicalOfAlgebra(matrixalgebra);;
h:=NaturalHomomorphismByIdeal(matrixalgebra,jacobsonradical);;
sscoef:=ImagesSource(h);;
idempotents:=CentralIdempotentsOfAlgebra(sscoef);;
gensofsscoef:=GeneratorsOfAlgebra(sscoef);;
Caluclating the generators' respective commutators
commutatorlist:=;;
for i in [1..Length(gensofsscoef)] do
for j in [i..Length(gensofsscoef)] do
Add(commutatorlist, gensofsscoef[i]*gensofsscoef[j] - gensofsscoef[j]*gensofsscoef[i]);
od;
od;
commutatorlist;
We have that it is commutative.Now we calculate the arrows. e_iJ(A)e_j/e_iJ(A)^2e_j
gensofjacobsonradical:=GeneratorsOfAlgebra(jacobsonradical);;
idemstimesjacobson:=;
for e_i in [1..Length(idempotents)] do
Add(idemstimesjacobson,);
for e_j in [1..Length(idempotents)] do
Add(idemstimesjacobson[e_i],);
for genofjacobson in gensofjacobsonradical do
Add(idemstimesjacobson[e_i][e_j], idempotents[e_i]genofjacobsonidempotents[e_j]);
od;
od;
od;
Here, we construct a Length(idempotents)xLength(gensofjacobsonradical)xLength(idempotents) array.
jacobsonradicalsquared:=;
for genofjacobson1 in gensofjacobsonradical do
for genofjacobson2 in gensofjacobsonradical do
Add(jacobsonradicalsquared, genofjacobson1*genofjacobson2);
od;
od;
idemstimesjacobsonsquared:=;
for e_i in [1..Length(idempotents)] do
Add(idemstimesjacobsonsquared,);
for e_j in [1..Length(idempotents)] do
Add(idemstimesjacobsonsquared[e_i],);
for genofjacobson in jacobsonradicalsquared do
Add(idemstimesjacobsonsquared[e_i][e_j], idempotents[e_i]genofjacobsonidempotents[e_j]);
od;
od;
od;
With this, we have e_iJ(A)e_j and e_iJ(A)^2e_j. Need to save the dimension of the quotient as the number of vertices.
vertices:=;
for e_i in [1..Length(idempotents)] do
Add(vertices, );
for e_j in [1..Length(idempotents)] do
numerator:=Ideal(matrixalgebra,idemstimesjacobson[e_i][e_j]);
denominator:=Ideal(matrixalgebra, idemstimesjacobsonsquared[e_i][e_j]);
if Dimension(numerator/denominator) > 0 then
Add(vertices[e_i], [e_i, e_j, Dimension(numerator/denominator)]);
fi;
od;
od;
vertices;
The end-result should be the quiver of $A$. However, the $Dimension$ function returns the following error:
Error, usage: TwoSidedIdeal( , [, "basis"] ) at /proc/cygdrive/C/gap-4.9.3/lib/ideal.gi:42 called from
Ideal( matrixalgebra, idemstimesjacobson[e_i][e_j] ) at stdin:152 called from
( )
called from read-eval loop at stdin:158
linear-algebra abstract-algebra gap
$endgroup$
$begingroup$
Could you please provide more details? One should be able to reproduce your setup to see what happens. "I cannot seem to calculate ..." does not give enough details - it's necessary to now what's exactly the problem is.
$endgroup$
– Alexander Konovalov
Dec 23 '18 at 23:09
$begingroup$
Also, do you mean "semi-simple coefficient" or "semi-simple component"?
$endgroup$
– Alexander Konovalov
Dec 23 '18 at 23:13
$begingroup$
I mean the semi-simple coefficient, $A/J(A)$, where $A$ is a right-artinian algebra, and $J(A)$ its jacobson radical. I have added comments and the entire code to the post. Hope that clarifies the question.
$endgroup$
– UnexpectedExpectation
Dec 24 '18 at 14:21
$begingroup$
Thanks - please also indent all GAP input and output by 4 spaces, this is needed to display it properly. Also, use indentation for loop bodies andif
statements - this makes the code more readable and easier to understand.
$endgroup$
– Alexander Konovalov
Dec 24 '18 at 22:56
1
$begingroup$
Your error is not inDimension
but (as the error message tells you) earlier when you create the ideal that you callnumerator
. You might want to step through the commands one by one and check whether you actually create the objects you want.
$endgroup$
– ahulpke
Dec 25 '18 at 9:10
|
show 1 more comment
$begingroup$
I have defined a matrix algebra over the rationals, calculated its radical, and took the semi-simple coefficient using h:=NaturalHomomorphismByIdeal and $ImagesSource(h)$. Afterwards, I calculated the idempotents of the semisimple coefficient using 'CentralIdempotentsOfAlgebra'. I also found the generators of the radical $J(A)$, as well as its square $J(A)^2$.
Now, I am trying to use the information to calculate the quiver of the original algebra. For that, I need to calculate the product of the idempotents $e_i$ and $e_j$ with the Jacobson radical, with arrows existing from $e_i$ to $e_j$ iff $q:=e_iJ(A)e_j/e_iJ(A)^2e_jneq 0$. And the number of arrows is the dimension of the vector space $q$. I cannot seem to calculate the dimension using the standard $Dimension$ function, or a basis using the standard $Basis$ function, since I have $e_i$ and $e_j$ as elements of the semi-simple coefficient, given as a linear combination of the generators $[v.1,cdots,v.6]$, while the generators of $J(A)$ are matrices.
A second problem is that $IsAlgebraWithOne(sscoef)$ returns $False$, while $One(sscoef)$ returns $v.1$, and $IsAlgebra(sscoef)$ returns $True$.
What am I missing?
Here is the code:
Constructing a non-commutative polynomial algebra
LoadPackage("GBNP");
A:=FreeAssociativeAlgebraWithOne(Rationals,"a","b","c");;
a:=A.a;;b:=A.b;;c:=A.c;;z:=Zero(A);;e:=One(A);;
relation1:=a^2-e;;relation2:=b^2-e;;relation3:=c^2-e;;relation4:=ab+bc+ca+e;; relation5:=ac+cb+ba+e;;
relationlist:=GP2NPList([relation1,relation2,relation3,relation4,relation5]);;
grobnerbasis:=SGrobner(relationlist);;
qabasis:=BaseQA(grobnerbasis,3,0);;
qamatrices:=MatricesQA(3,qabasis,grobnerbasis);;
Transform it into a matrix algebra, so that we can use the standard GAP-functions to calculate the radical.
matrixalgebra:=AlgebraWithOne(Rationals, qamatrices);;
jacobsonradical:=RadicalOfAlgebra(matrixalgebra);;
h:=NaturalHomomorphismByIdeal(matrixalgebra,jacobsonradical);;
sscoef:=ImagesSource(h);;
idempotents:=CentralIdempotentsOfAlgebra(sscoef);;
gensofsscoef:=GeneratorsOfAlgebra(sscoef);;
Caluclating the generators' respective commutators
commutatorlist:=;;
for i in [1..Length(gensofsscoef)] do
for j in [i..Length(gensofsscoef)] do
Add(commutatorlist, gensofsscoef[i]*gensofsscoef[j] - gensofsscoef[j]*gensofsscoef[i]);
od;
od;
commutatorlist;
We have that it is commutative.Now we calculate the arrows. e_iJ(A)e_j/e_iJ(A)^2e_j
gensofjacobsonradical:=GeneratorsOfAlgebra(jacobsonradical);;
idemstimesjacobson:=;
for e_i in [1..Length(idempotents)] do
Add(idemstimesjacobson,);
for e_j in [1..Length(idempotents)] do
Add(idemstimesjacobson[e_i],);
for genofjacobson in gensofjacobsonradical do
Add(idemstimesjacobson[e_i][e_j], idempotents[e_i]genofjacobsonidempotents[e_j]);
od;
od;
od;
Here, we construct a Length(idempotents)xLength(gensofjacobsonradical)xLength(idempotents) array.
jacobsonradicalsquared:=;
for genofjacobson1 in gensofjacobsonradical do
for genofjacobson2 in gensofjacobsonradical do
Add(jacobsonradicalsquared, genofjacobson1*genofjacobson2);
od;
od;
idemstimesjacobsonsquared:=;
for e_i in [1..Length(idempotents)] do
Add(idemstimesjacobsonsquared,);
for e_j in [1..Length(idempotents)] do
Add(idemstimesjacobsonsquared[e_i],);
for genofjacobson in jacobsonradicalsquared do
Add(idemstimesjacobsonsquared[e_i][e_j], idempotents[e_i]genofjacobsonidempotents[e_j]);
od;
od;
od;
With this, we have e_iJ(A)e_j and e_iJ(A)^2e_j. Need to save the dimension of the quotient as the number of vertices.
vertices:=;
for e_i in [1..Length(idempotents)] do
Add(vertices, );
for e_j in [1..Length(idempotents)] do
numerator:=Ideal(matrixalgebra,idemstimesjacobson[e_i][e_j]);
denominator:=Ideal(matrixalgebra, idemstimesjacobsonsquared[e_i][e_j]);
if Dimension(numerator/denominator) > 0 then
Add(vertices[e_i], [e_i, e_j, Dimension(numerator/denominator)]);
fi;
od;
od;
vertices;
The end-result should be the quiver of $A$. However, the $Dimension$ function returns the following error:
Error, usage: TwoSidedIdeal( , [, "basis"] ) at /proc/cygdrive/C/gap-4.9.3/lib/ideal.gi:42 called from
Ideal( matrixalgebra, idemstimesjacobson[e_i][e_j] ) at stdin:152 called from
( )
called from read-eval loop at stdin:158
linear-algebra abstract-algebra gap
$endgroup$
I have defined a matrix algebra over the rationals, calculated its radical, and took the semi-simple coefficient using h:=NaturalHomomorphismByIdeal and $ImagesSource(h)$. Afterwards, I calculated the idempotents of the semisimple coefficient using 'CentralIdempotentsOfAlgebra'. I also found the generators of the radical $J(A)$, as well as its square $J(A)^2$.
Now, I am trying to use the information to calculate the quiver of the original algebra. For that, I need to calculate the product of the idempotents $e_i$ and $e_j$ with the Jacobson radical, with arrows existing from $e_i$ to $e_j$ iff $q:=e_iJ(A)e_j/e_iJ(A)^2e_jneq 0$. And the number of arrows is the dimension of the vector space $q$. I cannot seem to calculate the dimension using the standard $Dimension$ function, or a basis using the standard $Basis$ function, since I have $e_i$ and $e_j$ as elements of the semi-simple coefficient, given as a linear combination of the generators $[v.1,cdots,v.6]$, while the generators of $J(A)$ are matrices.
A second problem is that $IsAlgebraWithOne(sscoef)$ returns $False$, while $One(sscoef)$ returns $v.1$, and $IsAlgebra(sscoef)$ returns $True$.
What am I missing?
Here is the code:
Constructing a non-commutative polynomial algebra
LoadPackage("GBNP");
A:=FreeAssociativeAlgebraWithOne(Rationals,"a","b","c");;
a:=A.a;;b:=A.b;;c:=A.c;;z:=Zero(A);;e:=One(A);;
relation1:=a^2-e;;relation2:=b^2-e;;relation3:=c^2-e;;relation4:=ab+bc+ca+e;; relation5:=ac+cb+ba+e;;
relationlist:=GP2NPList([relation1,relation2,relation3,relation4,relation5]);;
grobnerbasis:=SGrobner(relationlist);;
qabasis:=BaseQA(grobnerbasis,3,0);;
qamatrices:=MatricesQA(3,qabasis,grobnerbasis);;
Transform it into a matrix algebra, so that we can use the standard GAP-functions to calculate the radical.
matrixalgebra:=AlgebraWithOne(Rationals, qamatrices);;
jacobsonradical:=RadicalOfAlgebra(matrixalgebra);;
h:=NaturalHomomorphismByIdeal(matrixalgebra,jacobsonradical);;
sscoef:=ImagesSource(h);;
idempotents:=CentralIdempotentsOfAlgebra(sscoef);;
gensofsscoef:=GeneratorsOfAlgebra(sscoef);;
Caluclating the generators' respective commutators
commutatorlist:=;;
for i in [1..Length(gensofsscoef)] do
for j in [i..Length(gensofsscoef)] do
Add(commutatorlist, gensofsscoef[i]*gensofsscoef[j] - gensofsscoef[j]*gensofsscoef[i]);
od;
od;
commutatorlist;
We have that it is commutative.Now we calculate the arrows. e_iJ(A)e_j/e_iJ(A)^2e_j
gensofjacobsonradical:=GeneratorsOfAlgebra(jacobsonradical);;
idemstimesjacobson:=;
for e_i in [1..Length(idempotents)] do
Add(idemstimesjacobson,);
for e_j in [1..Length(idempotents)] do
Add(idemstimesjacobson[e_i],);
for genofjacobson in gensofjacobsonradical do
Add(idemstimesjacobson[e_i][e_j], idempotents[e_i]genofjacobsonidempotents[e_j]);
od;
od;
od;
Here, we construct a Length(idempotents)xLength(gensofjacobsonradical)xLength(idempotents) array.
jacobsonradicalsquared:=;
for genofjacobson1 in gensofjacobsonradical do
for genofjacobson2 in gensofjacobsonradical do
Add(jacobsonradicalsquared, genofjacobson1*genofjacobson2);
od;
od;
idemstimesjacobsonsquared:=;
for e_i in [1..Length(idempotents)] do
Add(idemstimesjacobsonsquared,);
for e_j in [1..Length(idempotents)] do
Add(idemstimesjacobsonsquared[e_i],);
for genofjacobson in jacobsonradicalsquared do
Add(idemstimesjacobsonsquared[e_i][e_j], idempotents[e_i]genofjacobsonidempotents[e_j]);
od;
od;
od;
With this, we have e_iJ(A)e_j and e_iJ(A)^2e_j. Need to save the dimension of the quotient as the number of vertices.
vertices:=;
for e_i in [1..Length(idempotents)] do
Add(vertices, );
for e_j in [1..Length(idempotents)] do
numerator:=Ideal(matrixalgebra,idemstimesjacobson[e_i][e_j]);
denominator:=Ideal(matrixalgebra, idemstimesjacobsonsquared[e_i][e_j]);
if Dimension(numerator/denominator) > 0 then
Add(vertices[e_i], [e_i, e_j, Dimension(numerator/denominator)]);
fi;
od;
od;
vertices;
The end-result should be the quiver of $A$. However, the $Dimension$ function returns the following error:
Error, usage: TwoSidedIdeal( , [, "basis"] ) at /proc/cygdrive/C/gap-4.9.3/lib/ideal.gi:42 called from
Ideal( matrixalgebra, idemstimesjacobson[e_i][e_j] ) at stdin:152 called from
( )
called from read-eval loop at stdin:158
linear-algebra abstract-algebra gap
linear-algebra abstract-algebra gap
edited Dec 24 '18 at 14:51
UnexpectedExpectation
asked Dec 23 '18 at 21:53
UnexpectedExpectationUnexpectedExpectation
769
769
$begingroup$
Could you please provide more details? One should be able to reproduce your setup to see what happens. "I cannot seem to calculate ..." does not give enough details - it's necessary to now what's exactly the problem is.
$endgroup$
– Alexander Konovalov
Dec 23 '18 at 23:09
$begingroup$
Also, do you mean "semi-simple coefficient" or "semi-simple component"?
$endgroup$
– Alexander Konovalov
Dec 23 '18 at 23:13
$begingroup$
I mean the semi-simple coefficient, $A/J(A)$, where $A$ is a right-artinian algebra, and $J(A)$ its jacobson radical. I have added comments and the entire code to the post. Hope that clarifies the question.
$endgroup$
– UnexpectedExpectation
Dec 24 '18 at 14:21
$begingroup$
Thanks - please also indent all GAP input and output by 4 spaces, this is needed to display it properly. Also, use indentation for loop bodies andif
statements - this makes the code more readable and easier to understand.
$endgroup$
– Alexander Konovalov
Dec 24 '18 at 22:56
1
$begingroup$
Your error is not inDimension
but (as the error message tells you) earlier when you create the ideal that you callnumerator
. You might want to step through the commands one by one and check whether you actually create the objects you want.
$endgroup$
– ahulpke
Dec 25 '18 at 9:10
|
show 1 more comment
$begingroup$
Could you please provide more details? One should be able to reproduce your setup to see what happens. "I cannot seem to calculate ..." does not give enough details - it's necessary to now what's exactly the problem is.
$endgroup$
– Alexander Konovalov
Dec 23 '18 at 23:09
$begingroup$
Also, do you mean "semi-simple coefficient" or "semi-simple component"?
$endgroup$
– Alexander Konovalov
Dec 23 '18 at 23:13
$begingroup$
I mean the semi-simple coefficient, $A/J(A)$, where $A$ is a right-artinian algebra, and $J(A)$ its jacobson radical. I have added comments and the entire code to the post. Hope that clarifies the question.
$endgroup$
– UnexpectedExpectation
Dec 24 '18 at 14:21
$begingroup$
Thanks - please also indent all GAP input and output by 4 spaces, this is needed to display it properly. Also, use indentation for loop bodies andif
statements - this makes the code more readable and easier to understand.
$endgroup$
– Alexander Konovalov
Dec 24 '18 at 22:56
1
$begingroup$
Your error is not inDimension
but (as the error message tells you) earlier when you create the ideal that you callnumerator
. You might want to step through the commands one by one and check whether you actually create the objects you want.
$endgroup$
– ahulpke
Dec 25 '18 at 9:10
$begingroup$
Could you please provide more details? One should be able to reproduce your setup to see what happens. "I cannot seem to calculate ..." does not give enough details - it's necessary to now what's exactly the problem is.
$endgroup$
– Alexander Konovalov
Dec 23 '18 at 23:09
$begingroup$
Could you please provide more details? One should be able to reproduce your setup to see what happens. "I cannot seem to calculate ..." does not give enough details - it's necessary to now what's exactly the problem is.
$endgroup$
– Alexander Konovalov
Dec 23 '18 at 23:09
$begingroup$
Also, do you mean "semi-simple coefficient" or "semi-simple component"?
$endgroup$
– Alexander Konovalov
Dec 23 '18 at 23:13
$begingroup$
Also, do you mean "semi-simple coefficient" or "semi-simple component"?
$endgroup$
– Alexander Konovalov
Dec 23 '18 at 23:13
$begingroup$
I mean the semi-simple coefficient, $A/J(A)$, where $A$ is a right-artinian algebra, and $J(A)$ its jacobson radical. I have added comments and the entire code to the post. Hope that clarifies the question.
$endgroup$
– UnexpectedExpectation
Dec 24 '18 at 14:21
$begingroup$
I mean the semi-simple coefficient, $A/J(A)$, where $A$ is a right-artinian algebra, and $J(A)$ its jacobson radical. I have added comments and the entire code to the post. Hope that clarifies the question.
$endgroup$
– UnexpectedExpectation
Dec 24 '18 at 14:21
$begingroup$
Thanks - please also indent all GAP input and output by 4 spaces, this is needed to display it properly. Also, use indentation for loop bodies and
if
statements - this makes the code more readable and easier to understand.$endgroup$
– Alexander Konovalov
Dec 24 '18 at 22:56
$begingroup$
Thanks - please also indent all GAP input and output by 4 spaces, this is needed to display it properly. Also, use indentation for loop bodies and
if
statements - this makes the code more readable and easier to understand.$endgroup$
– Alexander Konovalov
Dec 24 '18 at 22:56
1
1
$begingroup$
Your error is not in
Dimension
but (as the error message tells you) earlier when you create the ideal that you call numerator
. You might want to step through the commands one by one and check whether you actually create the objects you want.$endgroup$
– ahulpke
Dec 25 '18 at 9:10
$begingroup$
Your error is not in
Dimension
but (as the error message tells you) earlier when you create the ideal that you call numerator
. You might want to step through the commands one by one and check whether you actually create the objects you want.$endgroup$
– ahulpke
Dec 25 '18 at 9:10
|
show 1 more comment
1 Answer
1
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$begingroup$
As for the second question, IsAlgebraWithOne
is not a test function, but (as the manual tells) a category. As your example shows, other algebras also contain an One
element.
But for example the AlgebraWithOne
generated by the matrix $left(begin{array}{cc}0&1\0&0end{array}right)$ is two-dimensional (and contains the identity matrix), while the Algebra
generated by it is one-dimensional (and contains a one that is not the identity matrix).
$endgroup$
add a comment |
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1 Answer
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1 Answer
1
active
oldest
votes
active
oldest
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active
oldest
votes
$begingroup$
As for the second question, IsAlgebraWithOne
is not a test function, but (as the manual tells) a category. As your example shows, other algebras also contain an One
element.
But for example the AlgebraWithOne
generated by the matrix $left(begin{array}{cc}0&1\0&0end{array}right)$ is two-dimensional (and contains the identity matrix), while the Algebra
generated by it is one-dimensional (and contains a one that is not the identity matrix).
$endgroup$
add a comment |
$begingroup$
As for the second question, IsAlgebraWithOne
is not a test function, but (as the manual tells) a category. As your example shows, other algebras also contain an One
element.
But for example the AlgebraWithOne
generated by the matrix $left(begin{array}{cc}0&1\0&0end{array}right)$ is two-dimensional (and contains the identity matrix), while the Algebra
generated by it is one-dimensional (and contains a one that is not the identity matrix).
$endgroup$
add a comment |
$begingroup$
As for the second question, IsAlgebraWithOne
is not a test function, but (as the manual tells) a category. As your example shows, other algebras also contain an One
element.
But for example the AlgebraWithOne
generated by the matrix $left(begin{array}{cc}0&1\0&0end{array}right)$ is two-dimensional (and contains the identity matrix), while the Algebra
generated by it is one-dimensional (and contains a one that is not the identity matrix).
$endgroup$
As for the second question, IsAlgebraWithOne
is not a test function, but (as the manual tells) a category. As your example shows, other algebras also contain an One
element.
But for example the AlgebraWithOne
generated by the matrix $left(begin{array}{cc}0&1\0&0end{array}right)$ is two-dimensional (and contains the identity matrix), while the Algebra
generated by it is one-dimensional (and contains a one that is not the identity matrix).
answered Dec 25 '18 at 9:17
ahulpkeahulpke
7,1671026
7,1671026
add a comment |
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$begingroup$
Could you please provide more details? One should be able to reproduce your setup to see what happens. "I cannot seem to calculate ..." does not give enough details - it's necessary to now what's exactly the problem is.
$endgroup$
– Alexander Konovalov
Dec 23 '18 at 23:09
$begingroup$
Also, do you mean "semi-simple coefficient" or "semi-simple component"?
$endgroup$
– Alexander Konovalov
Dec 23 '18 at 23:13
$begingroup$
I mean the semi-simple coefficient, $A/J(A)$, where $A$ is a right-artinian algebra, and $J(A)$ its jacobson radical. I have added comments and the entire code to the post. Hope that clarifies the question.
$endgroup$
– UnexpectedExpectation
Dec 24 '18 at 14:21
$begingroup$
Thanks - please also indent all GAP input and output by 4 spaces, this is needed to display it properly. Also, use indentation for loop bodies and
if
statements - this makes the code more readable and easier to understand.$endgroup$
– Alexander Konovalov
Dec 24 '18 at 22:56
1
$begingroup$
Your error is not in
Dimension
but (as the error message tells you) earlier when you create the ideal that you callnumerator
. You might want to step through the commands one by one and check whether you actually create the objects you want.$endgroup$
– ahulpke
Dec 25 '18 at 9:10