+ \FSEM{c*}{t,f} &=& \FSEM{{c+}?}{t,f}\\[3ex]
+ \QSEM{c}{} &=& \PSEM{c}\\
+ \QSEM{!c}{} &=& \FUN{x}{\neg\APPLY{\PSEM{c}}{x}}\\
+ \QSEM{\langle*\rangle}{} &=& \FUN{\_}{\TRUE}\\
+ \QSEM{\langle n\rangle}{} &=& \FUN{x}{\NAME{x}=n}\\
+ \QSEM{@n}{} &=& \FUN{x}{\HASATTRIBUTE{x}{n}}\\
+ \QSEM{@n=v}{} &=& \FUN{x}{\ATTRIBUTE{x}{n}=v}\\
+ \QSEM{[p_1\#p_2]}{} &=& \FUN{x}{\APPLY{\LSEM{p_1}{}}{\PREV{x}}\wedge\APPLY{\RSEM{p_2}{}}{\NEXT{x}}}\\[3ex]
+ \LSEM{}{} &=& \FUN{\_}{\TRUE}\\
+ \LSEM{\cent}{} &=& \mathit{null}\\
+ \LSEM{p\;q}{} &=& \FUN{x}{\MATCH{x}{y}{\QSEM{q}{y}\AAND\APPLY{\LSEM{p}}{\PREV{y}}}{\FALSE}}\\
+ \RSEM{}{} &=& \FUN{\_}{\TRUE}\\
+ \RSEM{\$}{} &=& \mathit{null}\\
+ \RSEM{p\;q}{} &=& \FUN{x}{\MATCH{x}{y}{\QSEM{q}{y}\AAND\APPLY{\RSEM{p}}{\NEXT{y}}}{\FALSE}}\\
+ \mathit{null} &=& \FUN{x}{\MATCH{x}{\_}{\FALSE}{\TRUE}}\\
+ \mathit{exists} &=& \FUN{t}{\REC{a}{\FUN{x}{\MATCH{x}{y}{\APPLY{t}{y}\AOR\APPLY{a}{\NEXT{x}}}{\FALSE}}}}