start-ver=1.4 cd-journal=joma no-vol=12 cd-vols= no-issue= article-no= start-page=123 end-page=133 dt-received= dt-revised= dt-accepted= dt-pub-year=2006 dt-pub=20060824 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Some classical views on the parameters of the Grothendieck-Teichm?eller group en-subtitle= kn-subtitle= en-abstract= kn-abstract=

We present two new formulas concerning behaviors of the standard parameters of the Grothendieck-Teichm?ller group GT , and discuss their relationships with classical mathematics. First, considering a non-Galois etale cover of P1 {0 1 infinity} of degree 4, we present a newtype equation satisfied by the Galois image in GT . Second, a certain equation in GL 2 (Z||Z2 ) satisfied by every element of GT is derived as an application of (profinite) free differential calculus.

en-copyright= kn-copyright= en-aut-name=NakamuraHiroaki en-aut-sei=Nakamura en-aut-mei=Hiroaki kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= affil-num=1 en-affil= kn-affil=Okayama University en-keyword=Grothendieck-Teichm?eller group kn-keyword=Grothendieck-Teichm?eller group en-keyword=Belyi function kn-keyword=Belyi function en-keyword=modular function kn-keyword=modular function END