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seen Apr 12 at 15:01

Apr
10
comment complex numbers and 2x2 matrices
Should we not have $a^2+b^2 \ge 0$, because the absolute value of a complex number cannot be smaller than zero?
Apr
9
comment What does it mean to multiply a real matrix by a complex scalar?
I'm confused about the sentence "Multiplication with a fixed complex number is a linear transformation on this two-dimensional vector space". I thought that a complex number itself (not only the multiplication operation) can be represented as a 2x2 matrix, see en.wikipedia.org/wiki/…. Doesn't that mean that the complex numbers are not a vector space, but a matrix space over the real numbers?
Apr
8
asked What does it mean to multiply a real matrix by a complex scalar?
Feb
13
accepted What is the distribution of destiny numbers
Feb
8
asked What is the distribution of destiny numbers
Jan
2
answered How to prove Euler's formula: $e^{it}=\cos t +i\sin t$?
Oct
27
comment To “subtract” two matrices with different dimensions in Octave (Matlab)
This works also in Octave 3.4
Oct
27
comment To “subtract” two matrices with different dimensions in Octave (Matlab)
In Octave (3.4) this gives an error: a - b error: operator -: nonconformant arguments (op1 is 4x2, op2 is 1x2)
Jul
6
awarded  Editor
Jul
6
revised Does my definition of double complex noncommutative numbers make any sense?
fixed typo
Jul
6
awarded  Informed
Mar
25
awarded  Yearling
May
21
accepted Does my definition of double complex noncommutative numbers make any sense?
May
20
comment Does my definition of double complex noncommutative numbers make any sense?
@QiaochuYuan Thank you. "One cannot invent useful things, one can only rediscover them." ;-)
May
20
comment Does my definition of double complex noncommutative numbers make any sense?
Is there a special name for quaternions which have the coefficient of $k$ set to zero? And can't there also be quintions which could then factorize $a^2+b^2+c^2+d^2+e^2$ into two factors ?
May
19
awarded  Nice Question
May
19
asked Does my definition of double complex noncommutative numbers make any sense?
Mar
31
awarded  Scholar
Mar
31
accepted What are curves (generalized ellipses) with more than two focal points called and how do they look like?
Mar
25
awarded  Supporter