?rès ???q?? ét??? ?? r?st??r?t???? ?? ???s? ?? s?r??t ??tér?ss??t ?? ?????r?r ??s rés??t?ts ??t???s ???? ?? ?é??????t??? ?? ?? à ?? ?é??????t??? ??? ???ts ?? ?t???s??t ??s ????????s st????r?s ???s ?? ???????? ??? ?? ??????r ?? ?ét????? P?rs???t???s ?é?ér???s ? ???é??s?t??? st????st?q?? ?t r?st??r?? t??? P??s???rs ??t??rs s? s??t ré??????t ?tt???és à ré???s?r ??s ???è??s ,
s ?? ????ts ??t??? t?? ???????t ???r????? ?? t?? ????s ?r? s?t ?? ???t??t? t?? str????s?? ,
s ??r ????r? ?r? ?????t?? ?s??? ?f = f r ? f 0 f r ? ???r? f ?s t?? ???s???r?? ??r?????? r?s???t????? ?? t?? r?st?r?? r ??? ???t??? 0 st?t?s? ??r t?? ?????ts? t?? ???s?r? ?s s???? ?? ??t? ???t??? ??? r?s? t?r?? ??????r?t???s? ??? ????t???? ??s?????? ?s ????r s????? ?s ?ss??? ?? t?? r?tr??????r??t???? ????r? ??? ? ??st??r??s ?? t?? ????r??t ????t??? r?s??ts? ??? q???t????q???t??? ,