Question: What are the conjecture which start with the letter problem
Paraphrase: What are the guess which begin with the letter problem
SPARQL (Wikidata): SELECT DISTINCT ?sbj ?sbj_label WHERE { ?sbj wdt:P31 wd:Q319141 . ?sbj rdfs:label ?sbj_label . FILTER(CONTAINS(lcase(?sbj_label), 'problem')) . FILTER (lang(?sbj_label) = 'en') } LIMIT 25 
Answer: Hilbert's thirteenth problem, Hilbert's thirteenth problem, Hilbert's twelfth problem, Hilbert's twelfth problem, Waring's problem, Waring's problem, Erdős distinct distances problem, Erdős distinct distances problem, inscribed square problem, inscribed square problem, Sierpinski problem, Sierpinski problem, Lehmer's totient problem, Lehmer's totient problem, Erdős–Graham problem, Erdős–Graham problem, Hilbert's tenth problem, Hilbert's tenth problem, Hilbert's fourteenth problem, Hilbert's fourteenth problem, Hilbert's sixteenth problem, Hilbert's sixteenth problem, Pompeiu problem, Pompeiu problem, Hilbert's twentieth problem, Hilbert's twentieth problem, No-three-in-line problem, No-three-in-line problem, Hilbert's fifteenth problem, Hilbert's fifteenth problem, Naimark's problem, Naimark's problem, Mahler's 3/2 problem, Mahler's 3/2 problem