運算式 5: "g" left parenthesis, "x" , right parenthesis less than or equal to "y" less than or equal to "f" left parenthesis, "x" , right parenthesisgx≤y≤fx
5
運算式 6: "g" left parenthesis, "x" , right parenthesis greater than or equal to "y" greater than or equal to "f" left parenthesis, "x" , right parenthesisgx≥y≥fx