Questions tagged [matrix-congruences]

For questions about congruent matrices.

Two matrices $A$ and $B$ over a ring are called congruent if there exists an invertible matrix $P$ over the same ring such that $$P^TAP=B.$$ Matrix congruence is an equivalence relation.

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Is Same signs of determinants of $A$ and $B$ $\implies P^tAP =B$

Let $$A = \begin{pmatrix} 1 & 0 & 0 & 0 \\ 0 & 1 & 0 & 0 \\ 0 & 0 & 1 & 0 \\ 0 & 0 & 0 & b \\ \end{pmatrix} $$ and $$ B= \begin{pmatrix} 1 & 0 & 0 & 0 \\ 0 & 1 & 0 & 0 \\ 0…
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How to conclude that matrices $A$ and $B$ are congruent?

Let $A$ and $B$ be real $n×n$ matrices. Which of the following statements is false ? If $A^{-1}$ and $B^{-1}$ are congruent then so are $A$ and $B$. If $A^t$ and $B^t$ are congruent then so are $A$ and $B$. Where $A^t$ denotes transpose of matrix…