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location Chemnitz, Germany
age 27
visits member for 3 years, 6 months
seen Nov 13 at 12:57

Jan
27
revised Finding the radius of a particular center voxel in 3D cylinder-like structure
added 643 characters in body
Jan
27
revised Finding the radius of a particular center voxel in 3D cylinder-like structure
added 3 characters in body
Jan
27
answered Finding the radius of a particular center voxel in 3D cylinder-like structure
Jan
27
comment Finding the radius of a particular center voxel in 3D cylinder-like structure
@RahulNarain When he says "circle at a perpendicular angle", he probebly means perpedicular to the curve's tangent vector.
Jan
25
revised Factorize a Symmetric matrix as an 'Approximation' with an outer product.
adjusted formatting
Jan
25
suggested suggested edit on Factorize a Symmetric matrix as an 'Approximation' with an outer product.
Jan
24
suggested suggested edit on How to Determine an Equation of a Circle using a Line and Two Points on a Circle
Jan
18
revised Orthogonal matrices, scalar products, projection of a line on a plane
added 38 characters in body
Jan
18
revised Orthogonal matrices, scalar products, projection of a line on a plane
deleted 1 characters in body
Jan
18
answered Orthogonal matrices, scalar products, projection of a line on a plane
Jan
17
revised Divide a Set of Points along a Direction
added 149 characters in body
Jan
17
answered Divide a Set of Points along a Direction
Dec
9
comment Matrices for which $\mathbf{A}^{-1}=-\mathbf{A}$
@HenningMakholm He just means that a matrix with the searched property can be constructed from any reflection matrix. Though his last paragraph is a bit obsolete, but +1 for the first paragraph.
Dec
9
awarded  Scholar
Dec
9
accepted Matrices for which $\mathbf{A}^{-1}=-\mathbf{A}$
Dec
9
comment Matrices for which $\mathbf{A}^{-1}=-\mathbf{A}$
Ah, ok. Now I understand what you mean by conjugation. And I understand why this keeps the mentioned property but destroys the unitarity property. Thanks again.
Dec
9
comment Matrices for which $\mathbf{A}^{-1}=-\mathbf{A}$
I just cannot get what conjugation by a unitary matrix means. I guess with conjugation you mean not just the simple complex conjugate of the matrix elements? Sorry, but I'm not that deeply versed in linear algebra, especially if it gets too theoretical.
Dec
9
comment Matrices for which $\mathbf{A}^{-1}=-\mathbf{A}$
Thanks for your answer, but I have difficulties to understand the last sentence. What do you mean with "by conjugating by a non-unitary matrix". Now I understand that it is invariant under conjugation. But aren't the skew-Hermitian and unitary properties invariant under conjugation, too? I don't know how cojugation helps with constructing a counter-example. Or do you mean something different (I don't really understand what conjugation by a non-unitary matrix means)?
Dec
8
awarded  Student
Dec
8
comment Matrices for which $\mathbf{A}^{-1}=-\mathbf{A}$
@AlexanderThumm Of course, as simple as it can be, me stupid! But what about more general matrices?