The negation of exists: evaluates to true when the wrapped pattern has no solution in the
enclosing context. The clauses are space-joined into a single group. Empty clauses, such as those
produced by nil, are dropped first; when none survives, the result is the empty fragment via nil,
which callers must guard against where a pattern is required.
Generates a SPARQL
not existsgraph-pattern test.The negation of exists: evaluates to
truewhen the wrapped pattern has no solution in the enclosing context. The clauses are space-joined into a single group. Empty clauses, such as those produced by nil, are dropped first; when none survives, the result is the empty fragment via nil, which callers must guard against where a pattern is required.