In 2005, Gyllenhaal was cast in the drama "Proof", with co-stars Gwyneth Paltrow and Anthony Hopkins, He played a graduate student in mathematics who tries to convince Paltrow's character to publish a revolutionary proof to a problem puzzling the mathematicians' community. The film received a generally positive response. He also starred in Sam Mendes' "Jarhead", where Gyllenhaal played a violent U.S. Marine during the first Gulf War. The film garnered a favorable response; Stephen Hunter of "The Washington Post" praises Gyllenhaal's performance, writing, "He makes us see his character's intelligence", adding "he doesn't seem jealous of the camera's attention when it goes to others".