Modular group: Difference between revisions

In [[mathematics]], the '''modular group''' is the [[projective linear group|projective special linear group]] {{math|PSL(2, '''Z''')}} of {{nowrap|2{{Hair space}}×{{Hair space}}2}} [[Matrix (mathematics)|matrices]] with [[integer]] coefficients and unit [[determinant]] 1. The matrices {{math|''A''}} and {{math|−''A''}} are identified. The modular group acts on the upper-half of the [[complex plane]] by [[fractional linear transformation]]s, and the name "modular group" comes from the relation to [[moduli space]]s and not from [[modular arithmetic]].