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Aug
25 |
comment |
Invariant planes of a nilpotent matrix with two Jordan blocks of size two
This is the description of all of them, because any invariant subspace containing a vector $v$ shoud contain $Nv$. |
Aug
25 |
comment |
Invariant planes of a nilpotent matrix with two Jordan blocks of size two
Take any vector $v$ not belonging to the kernel of $N$ and consider the space $\langle v,Nv\rangle$. This family and the kernel of $N$ are all spaces you ask about. |
Aug
24 |
awarded | Self-Learner |
Aug
23 |
answered | A sequence of subsets of an infinite group |
Aug
23 |
answered | Are infinite groups “locally topologizable”? |
Aug
23 |
comment |
A sequence of subsets of an infinite group
A related question: mathoverflow.net/q/179177/24165 . |
Aug
23 |
asked | Are infinite groups “locally topologizable”? |
Jul
2 |
awarded | Curious |
Jun
2 |
awarded | Yearling |
Apr
24 |
comment |
An element $g$ in a group such that neither $g=1$ nor $g\ne 1$ can be proved.
@Dan, surely. What you said is basically Metatheorem 3.5.2 from my answer. |
Mar
8 |
awarded | Popular Question |
Jan
22 |
awarded | Organizer |
Jan
22 |
revised |
subsets of groups which have to be closed no matter what
arXiv's tags added |
Jan
22 |
suggested | approved edit on subsets of groups which have to be closed no matter what |
Jan
22 |
awarded | Nice Answer |
Jan
22 |
answered | subsets of groups which have to be closed no matter what |
Jan
21 |
revised |
Fantastic properties of Z/2Z
added 12 characters in body |
Jan
21 |
answered | Fantastic properties of Z/2Z |
Jan
21 |
answered | Examples of cancellative normal semigroups |
Jan
20 |
comment |
Why the axiomatic rank of the variety of groups is equal to three?
Your octonion argument is much simpler and works perfectly. The algebra of all unit octonions or all non-zero octonions (with operations $\cdot$, ${\ }^{-1}$, and $1$) is non-associative but satisfies all two-variable laws that are consequences of the group axioms. |