System of homogen linear equations in a division ring
$begingroup$
Let $K$ be a division ring (one does not suppose that $K$ is commutative) and $m,n$ two positive integers such that $m<n$. Consider the system of homogen linear equations
$$left{begin{array}{rcl}
a_{11}x_1+a_{12}x_2+cdots+a_{1n}x_n&=&0\
a_{21}x_1+a_{22}x_2+cdots+a_{2n}x_n&=&0\
vdotsqquadqquadqquad&vdots&vdots\
a_{m1}x_1+a_{m2}x_2+cdots+a_{mn}x_n&=&0\
end{array}right.$$
where the $a_{ij}$'s are in $K$. Can we assert that this system admits an infinity of solutions. Obviously, it is true when $K$ is commutative. But when $K$ is not, I do not know if this results still holds.
Is it also true in the non commutative case?
Thanks in advance.
linear-algebra noncommutative-algebra
$endgroup$
add a comment |
$begingroup$
Let $K$ be a division ring (one does not suppose that $K$ is commutative) and $m,n$ two positive integers such that $m<n$. Consider the system of homogen linear equations
$$left{begin{array}{rcl}
a_{11}x_1+a_{12}x_2+cdots+a_{1n}x_n&=&0\
a_{21}x_1+a_{22}x_2+cdots+a_{2n}x_n&=&0\
vdotsqquadqquadqquad&vdots&vdots\
a_{m1}x_1+a_{m2}x_2+cdots+a_{mn}x_n&=&0\
end{array}right.$$
where the $a_{ij}$'s are in $K$. Can we assert that this system admits an infinity of solutions. Obviously, it is true when $K$ is commutative. But when $K$ is not, I do not know if this results still holds.
Is it also true in the non commutative case?
Thanks in advance.
linear-algebra noncommutative-algebra
$endgroup$
add a comment |
$begingroup$
Let $K$ be a division ring (one does not suppose that $K$ is commutative) and $m,n$ two positive integers such that $m<n$. Consider the system of homogen linear equations
$$left{begin{array}{rcl}
a_{11}x_1+a_{12}x_2+cdots+a_{1n}x_n&=&0\
a_{21}x_1+a_{22}x_2+cdots+a_{2n}x_n&=&0\
vdotsqquadqquadqquad&vdots&vdots\
a_{m1}x_1+a_{m2}x_2+cdots+a_{mn}x_n&=&0\
end{array}right.$$
where the $a_{ij}$'s are in $K$. Can we assert that this system admits an infinity of solutions. Obviously, it is true when $K$ is commutative. But when $K$ is not, I do not know if this results still holds.
Is it also true in the non commutative case?
Thanks in advance.
linear-algebra noncommutative-algebra
$endgroup$
Let $K$ be a division ring (one does not suppose that $K$ is commutative) and $m,n$ two positive integers such that $m<n$. Consider the system of homogen linear equations
$$left{begin{array}{rcl}
a_{11}x_1+a_{12}x_2+cdots+a_{1n}x_n&=&0\
a_{21}x_1+a_{22}x_2+cdots+a_{2n}x_n&=&0\
vdotsqquadqquadqquad&vdots&vdots\
a_{m1}x_1+a_{m2}x_2+cdots+a_{mn}x_n&=&0\
end{array}right.$$
where the $a_{ij}$'s are in $K$. Can we assert that this system admits an infinity of solutions. Obviously, it is true when $K$ is commutative. But when $K$ is not, I do not know if this results still holds.
Is it also true in the non commutative case?
Thanks in advance.
linear-algebra noncommutative-algebra
linear-algebra noncommutative-algebra
asked Dec 27 '18 at 2:37
joaopajoaopa
35618
35618
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1 Answer
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The system has infinitely many solutions, even when $K$ is non-commutative. The reason is that row reduction is still possible over a non-commutative division ring.
Side remark: if $K$ is commutative, the system has infinitely many solutions only if $K$ is infinite. If $K$ is not commutative, then it is automatically infinite by Wedderburn's little theorem.
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1 Answer
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1 Answer
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$begingroup$
The system has infinitely many solutions, even when $K$ is non-commutative. The reason is that row reduction is still possible over a non-commutative division ring.
Side remark: if $K$ is commutative, the system has infinitely many solutions only if $K$ is infinite. If $K$ is not commutative, then it is automatically infinite by Wedderburn's little theorem.
$endgroup$
add a comment |
$begingroup$
The system has infinitely many solutions, even when $K$ is non-commutative. The reason is that row reduction is still possible over a non-commutative division ring.
Side remark: if $K$ is commutative, the system has infinitely many solutions only if $K$ is infinite. If $K$ is not commutative, then it is automatically infinite by Wedderburn's little theorem.
$endgroup$
add a comment |
$begingroup$
The system has infinitely many solutions, even when $K$ is non-commutative. The reason is that row reduction is still possible over a non-commutative division ring.
Side remark: if $K$ is commutative, the system has infinitely many solutions only if $K$ is infinite. If $K$ is not commutative, then it is automatically infinite by Wedderburn's little theorem.
$endgroup$
The system has infinitely many solutions, even when $K$ is non-commutative. The reason is that row reduction is still possible over a non-commutative division ring.
Side remark: if $K$ is commutative, the system has infinitely many solutions only if $K$ is infinite. If $K$ is not commutative, then it is automatically infinite by Wedderburn's little theorem.
answered Dec 27 '18 at 13:20
Pierre-Guy PlamondonPierre-Guy Plamondon
8,88511739
8,88511739
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