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Theorems · Definition · group theory

ModularGroup.S

Matrix.SpecialLinearGroup (Fin 2) ℤ

The matrix S = [[0, -1], [1, 0]] as an element of SL(2, ℤ). This element acts naturally on the Euclidean plane as a rotation about the origin by π / 2. This element also acts naturally on the hyperbolic plane as rotation about i by π. It represents the Mobiüs transformation z ↦ -1/z and is an involutive elliptic isometry.

Defined in
Mathlib.LinearAlgebra.Matrix.SpecialLinearGroup
Cited by
36 results in Mathlib
Foundations
Depth 94 from the axioms · uses propext, Classical.choice, Quot.sound

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