SUR LES GROUPES D ORDRE FINI. 
discussion de ces congruences donne les groupes 
= ^^'=0, c' — Q3_j^ ah — bac. ac — ca^^^ ad = da 
bc = cbG, bd — dbc^ cd — dc^^-'^ ^ = i,2 
'a'=6, i^=: c^= (i'— 6-'= I, ab — bac^ ac = ca(i 
ad — da^ bc— cb^)^ bd=zdbc^ cd = dc(\ 
= è^ii=0, c^ = d'*= (}'^ = 1, ab = bac, ac — caf'^ ad = da 
bc — cb^ bd—dbc^ cd=dci)^^ 2 
= ^' = 0, c'^ =: c?^ = 6^ z= I , ab^bac, ac z= ca 
ad—da^^ bc = cb^i^ bd = dbc^ cd — de 
' a^ — b'^—d^ c'* = <i'' = 0' = I , ab:=^bac, ac — ca 
ad — da^ bc — cb^^ bd — dbc^ cd — dc 
'a*=6^=0, = = zzri , ab — bac, ac^ca^) 
bc = c6, ad — da^ bd — db 0, cd — de 
'a^=0, b'^—&=^d^^{S^zz:L\^ab—bac^ ac = ca% 
ad = da^ bc — cb^ bd = dbc^ cd — dc^ 
'«3— ^3— g3_- ^/3— ()3_- ab=ibac^ ac = ca\ 
ad = daO, bc — cbO^ bd=dbc, cd — dc ) 
= 6, = = f/-^ = 0'* = I , ab—bac^ ac = ca\ 
ad — da^ bc = cbO, bd — dbc^ cd—dc ) 
'«3 — fj^ (,3— ^/3— ()3_ ,^ al)=bac^ ac^cafP 
ad=da^ bc = cb^ bd=db^^ cd=.dc ^ 
avec adz=da^)^ bd = db?j<) 
ou avec ad = da(i, bd = db?! 
ou avec ad—da^ bd — db^^ 
ou avec ad—da^ bd — db^ 
à^—h^—^^ C'' r= I , ab = bac^ ac — ca 
bc — cbO, bd=db^ cd — dc^ ad = db^) 
'a'=b^=0, (/a=:0« = ab — ba 
bd = db^ ad = daQ 
/a^=.b''—i), d' = ::j'^=i, ab = ba?J\ 
\ bd=db(i, ad — da J 
a^=0, b'^ — c'^ — d^ — ^)'^ — ^ ^ ab — bac^ ac — ca 
bc — cb^^ bd~db^ cd=zdc^ ad — dai) 
/a^^O, ^'J^c'— 03z=&3_i^ ab — ba'3\ 
\ ac — ca^ bc — cbO ) 
a^— b^= 0, 
ab = ba'b 
