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seen Dec 16 at 12:29

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Apr
15
comment Similarity between $I+N$ and $e^N$ when $N$ is nilpotent
Why won't the "chain" of $A^i$ terminate before $i$ reaches $n$ in the triangle case? I mean, why is it impossible that there exist a $k<n$ such that $A^k=0$?
Apr
15
revised Similarity between $I+N$ and $e^N$ when $N$ is nilpotent
added 33 characters in body
Apr
15
comment Similarity between $I+N$ and $e^N$ when $N$ is nilpotent
Can you give more words on "The similarity type of $N$ is determined by the dimensions of the kernels of powers of $N$"?
Apr
14
revised Similarity between $I+N$ and $e^N$ when $N$ is nilpotent
added 359 characters in body
Apr
14
revised Similarity between $I+N$ and $e^N$ when $N$ is nilpotent
added 306 characters in body
Apr
14
revised Similarity between $I+N$ and $e^N$ when $N$ is nilpotent
added 271 characters in body
Apr
14
asked Similarity between $I+N$ and $e^N$ when $N$ is nilpotent
Oct
18
accepted How many $n$'s can make $4m^2-n^2$ a perfect square? And, triple of a perfect square?
Oct
18
comment How many $n$'s can make $4m^2-n^2$ a perfect square? And, triple of a perfect square?
Thank you, @André Nicolas, it's a nice answer and reference. Is there literature on decomposing an integer into a perfect square and a prime multiple of another perfect square (Just as the second part of the question)?
Oct
17
revised How many $n$'s can make $4m^2-n^2$ a perfect square? And, triple of a perfect square?
edited title
Oct
17
revised How many $n$'s can make $4m^2-n^2$ a perfect square? And, triple of a perfect square?
edited title
Oct
17
comment How many $n$'s can make $4m^2-n^2$ a perfect square? And, triple of a perfect square?
A non-pythagorean question is added.
Oct
17
revised How many $n$'s can make $4m^2-n^2$ a perfect square? And, triple of a perfect square?
added 79 characters in body
Oct
17
revised How many $n$'s can make $4m^2-n^2$ a perfect square? And, triple of a perfect square?
added 79 characters in body
Oct
17
comment How many $n$'s can make $4m^2-n^2$ a perfect square? And, triple of a perfect square?
Ah, $(a^2-b^2)^2+(2ab)^2=(a^2+b^2)^2$. So I have to find all $(a,b)$'s such that $a^2+b^2=2m$.
Oct
17
comment Solution to a system of linear equations in GF(2)
An insightful answer. It is brilliant to consider $A^2$. To solve the puzzle I have to handle all the cases so I give the "√" to @user1551, but this is impressive.
Oct
17
comment Solution to a system of linear equations in GF(2)
Thank you, @user1551. Actually the question is from a variant of lights out puzzle, where the light pressed affects the whole row and column.
Oct
17
asked How many $n$'s can make $4m^2-n^2$ a perfect square? And, triple of a perfect square?
Oct
17
accepted Solution to a system of linear equations in GF(2)
Oct
7
comment Solution to a system of linear equations in GF(2)
I can't see why the rows $1,n+1,\cdots,(m-1)n+1$ are identical. Take $A$ for an example: after manipulation, the 1st row is $(1,1,1,0,0,0)$ and the 4th row is $(1,0,0,1,1,1)$. Did I make some calculation mistakes?