<?php
 
$newDomObj = new DOMDocument;
$newXpathObj = new DOMXPath($newDomObj);
 
$xpathValid = '//node[@cat="smain" and node[@rel="su" and @pt="vnw"] and node[@rel="hd" and @pt="ww"] and node[@rel="predc" and @cat="np" and node[@rel="det" and @pt="lid"] and node[@rel="hd" and @pt="n"]]]';
$xpathInvalid = '//node[@cat="smain" and node[@rel="su" and @pt="vnw" and number(@begin) < ../node[@rel="hd" and @pt="ww"]/number(@begin)] and node[@rel="hd" and @pt="ww" and number(@begin) < ../node[@rel="predc" and @cat="np"]/node[@rel="det" and @pt="lid"]/number(@begin)] and node[@rel="predc" and @cat="np" and node[@rel="det" and @pt="lid" and number(@begin) < ../node[@rel="hd" and @pt="n"]/number(@begin)] and node[@rel="hd" and @pt="n"]]]';
 
$valid = ($newXpathObj->evaluate($xpathValid) === false) ? false : true;
$invalid = ($newXpathObj->evaluate($xpathInvalid) === false) ? false : true;
 
var_dump($valid);
var_dump($invalid);

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