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4 exercise(s) shown, 0 hidden
Apr 20'25
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Fill in all the geometric details in the basic theory of the determinant, by using the same type of arguments as those in the proof of

[[math]] \det\begin{pmatrix}a&b\\c&d\end{pmatrix}=ad-bc [[/math]]

which was fully proved in the above, namely geometric manipulations, and Thales.

Apr 20'25
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Prove with full details, based on the above, that the determinant of the systems of vectors

[[math]] \det:\mathbb R^N\times\ldots\times\mathbb R^N\to\mathbb R [[/math]]

is multilinear, alternate and unital, and unique with these properties. Then try to prove as well this directly, without any reference to geometry.

Apr 20'25
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Work out, with full details, the theory of the signature map

[[math]] \varepsilon:S_N\to\{\pm1\} [[/math]]

as outlined in Theorem 2.35 and its proof.

Apr 20'25
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Prove that for a matrix [math]H\in M_N(\pm1)[/math], we have

[[math]] |\det H|\leq N^{N/2} [[/math]]

and then find the maximizers of [math]|\det H|[/math], at small values of [math]N[/math].