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 22h comment Does every invertible matrix A has a matrix B such that A=Adj(B)? Apr 29 answered Result about Matrices of form $B(AB)^{-1}A$ Apr 29 comment Result about Matrices of form $B(AB)^{-1}A$ So, have you run your script? What's the result? Apr 29 comment Closest positive definite matrix to arbitrary one The set of all positive definite matrices is not closed. So, in general, unless your matrix is PD right from the start, no solution exists. Maybe you are looking for the closest positive semidefinite matrix? Apr 27 answered Pseudoinverse (Moore-Penrose) of rank 1 matrix is a scalar multiple of its transpose Apr 26 comment An inverse spectrum problem in linear algebra, No, the realising matrix is not necessarily symmetric. Every 2x2 asymmetric nonnegative matrix will realise some real spectrum. E.g. $\pmatrix{1&1\\ 0&1}$ has spectrum $\{1,1\}$. It just happens that when $n=2$, every spectrum of a nonnegative matrix is realisable by some symmetric nonnegative matrix. Apr 26 reviewed Close Question regarding Sum Notation in the least squares formula Apr 26 reviewed Close What means to expand determinant from first column? Apr 26 reviewed Close Let $f(x)= \begin{cases} 1, & \text{if$x \in \Bbb Q \cap [a,b]$} \\ -1, & \text{if$x \in \Bbb I \cap[a,b]$} \end{cases}$ Apr 26 reviewed Close Prove that $f$ is a constant function. Apr 26 reviewed Close Expected value of $X^{2n}$ where $X \sim N(0,1)$ Apr 26 reviewed Close $g: (U \times U - D) \to \mathbb{R}$ is continuous, $D$ diagonal? Apr 26 reviewed Close If there are $74$ heads and $196$ legs, how many horses and humans are there? Apr 26 reviewed Leave Open Why four roots to this equation: $(7x+1)^{1 \over 3}+(8+x-x^2)^{1 \over 3}+(x^2-8x-1)^{1 \over 3}=2$ Apr 26 reviewed Close Combination of the arrangement of sets Apr 26 revised If $\frac{4z+17}{18} - \frac{13z-2}{17z-32} + \frac{z}{3} = \frac{z+60}{36}$ , find the value of $z$. edited tags Apr 25 comment If matrix $A$ is similar to matrix $D$ and $B$ is similar to $E$, than: $AB$ is similar to $DE$? And the answer to the question in the title is also "no". Consider the case where $A=B=D$ is the 2x2 nilpotent Jordan block and $E=A^T$. Apr 25 revised Point closest to a set four of lines in 3D added 417 characters in body Apr 23 revised Special skew-symmetric matrices added 159 characters in body Apr 22 answered Special skew-symmetric matrices