表达式9: "s" equals left brace, "w" greater than 0 : 1 , negative 1 , right braces=w>0:1,−1
equals=
11
9
表达式10: "a" "x" left brace, "x" greater than or equal to 0 , right braceaxx≥0
10
表达式11: StartFraction, 1 Over "a" , EndFraction left parenthesis, "x" minus 1 , right parenthesis plus 1 left brace, "x" less than or equal to 1 , right brace1ax−1+1x≤1
11
表达式12: negative StartFraction, 1 Over "a" , EndFraction "x"−1ax
12
表达式13: negative "a" left parenthesis, "x" minus 1 , right parenthesis plus 1−ax−1+1
