diff --git a/doc/Doc.autodoc b/doc/Doc.autodoc index 611e187..684ecfe 100644 --- a/doc/Doc.autodoc +++ b/doc/Doc.autodoc @@ -5,6 +5,9 @@ @Subsection A category of module homomorphisms @InsertChunk CategoryOfRepresentations +@Subsection One step in the direct sum decomposition +@InsertChunk DecomposeOnceByRandomEndomorphism + @Subsection Another category of module homomorphisms @InsertChunk RepresentingC4C4 diff --git a/examples/DecomposeOnceByRandomEndomorphism.g b/examples/DecomposeOnceByRandomEndomorphism.g index 3488798..05bd498 100644 --- a/examples/DecomposeOnceByRandomEndomorphism.g +++ b/examples/DecomposeOnceByRandomEndomorphism.g @@ -1,4 +1,4 @@ -#! @Chunk DecomposeOnceByRandomEndomorphism +#! @BeginChunk DecomposeOnceByRandomEndomorphism LoadPackage( "CatReps" ); @@ -22,9 +22,9 @@ DecomposeOnceByRandomEndomorphism( nine ); #! fail #! @EndExample -#! The above shows that our representation nine is indecomposable. +#! The above shows that our representation nine is indecomposable. #! We use the tensor product to generate another representation -#! fortyone, that is hopefully decomposable. +#! fortyone, that is hopefully decomposable. #! @Example fortyone := TensorProductOnObjects( nine, nine ); @@ -221,11 +221,12 @@ Display( S ); #! A morphism in Category of matrices over GF(3) #! @EndExample -#! Comparing the matrices of fortyone with those of S, we see -#! that after decomposing once, we have seperated one small -#! matrix on the diagonal: A $3\times 3$-matrix from $S(kq.a)$, -#! a $3 \times 1$-matrix from $S(kq.b)$ and a $1\times 1$-matrix -#! from S(kq.c). This matches with the sources of the +#! Comparing the matrices of fortyone with those of +#! S, we see +#! that after decomposing once, we have separated one small +#! matrix on the diagonal: A $3\times 3$-matrix from S(kq.a), +#! a $3 \times 1$-matrix from S(kq.b) and a $1\times 1$-matrix +#! from S(kq.c). This matches with the source of the #! natural transformation $\iota$. #! @Example @@ -246,7 +247,50 @@ Display( iota ); #! . . . . . . . . . . . . . . . 1 #! #! A split monomorphism in Category of matrices over GF(3) -Source( iota(kq.1) ); -#! -Source( iota(kq.2) ); -#! +Display( Source( iota) ); +#! An object in The category of functors: Algebroid generated by the +#! right quiver q(2)[a:1->1,b:1->2,c:2->2] -> Category of matrices +#! over GF(3) defined by the following data: +#! +#! Image of <(1)>: +#! A vector space object over GF(3) of dimension 3 +#! +#! Image of <(2)>: +#! A vector space object over GF(3) of dimension 1 +#! +#! Image of (1)-[{ Z(3)^0*(a) }]->(1): +#! . 2 . +#! 1 2 2 +#! . . 1 +#! +#! A morphism in Category of matrices over GF(3) +#! +#! +#! Image of (1)-[{ Z(3)^0*(b) }]->(2): +#! 2 +#! 1 +#! . +#! +#! A morphism in Category of matrices over GF(3) +#! +#! +#! Image of (2)-[{ Z(3)^0*(c) }]->(2): +#! 1 +#! +#! A morphism in Category of matrices over GF(3) +#! @EndExample + +#! We can then look at the other factor of the direct sum +#! decomposition, i.e. $\kappa$. The iteration of +#! WeakDirectSumDecomposition will continue then +#! with Source( kappa ). Each time the random +#! endomorphism will decompose the representation by +#! at most a dimension of $3$. + +#! @Example +Source( kappa ); +#! <(1)->22, (2)->15; (a)->22x22, (b)->22x15, (c)->15x15> +result2 := DecomposeOnceByRandomEndomorphism( Source( kappa ) ); +#! [ <(1)->3x22, (2)->3x15>, <(1)->19x22, (2)->12x15> ] +#! @EndExample +#! @EndChunk