ƚ` [  .  `& & MathTypePSymbol P؟ww w f-2 3(ySymbol {؟ww w f-2 )yTimes New Roman؟ww w f-2 !162 36 Times New Roman؟ww w f-2 26Symbol R؟ww w f-2 =62 -6Times New Roman؟ww w f-2 x6 & "System f !-