https://www.omnicalculator.com/math/characteristic-polynomial
Characteristic Polynomial Calculator
Characteristic polynomial calculator helps you determine the characteristic polynomial of any matrix of size 2×2, 3×3, or 4×4.
characteristic polynomialcalculator
https://portal.mardi4nfdi.de/wiki/A_geometric_interpretation_of_the_characteristic_polynomial_of_reflection_arrangements
A geometric interpretation of the characteristic polynomial of reflection arrangements - MaRDI...
of thecharacteristic polynomialgeometricinterpretationreflection