Question: What are the scientific theory which start with the letter u
Paraphrase: What are the logical hypothesis which begin with the letter u
SPARQL (Wikidata): SELECT DISTINCT ?sbj ?sbj_label WHERE { ?sbj wdt:P31 wd:Q3239681 . ?sbj rdfs:label ?sbj_label . FILTER(STRSTARTS(lcase(?sbj_label), 'u')) . FILTER (lang(?sbj_label) = 'en') } LIMIT 25 
Answer: uncertainty principle, uncertainty principle