Simplify the following text for a Grade 12 native English-speaking person.
Original: In the nineteenth century , hyperbolic geometry was extensively explored by JÃ nos Bolyai and Nikolai Ivanovich Lobachevsky , after whom it sometimes is named .
Simplified: In the nineteenth century , hyperbolic geometry was explored by JÃ nos Bolyai and Nikolai Ivanovich Lobachevsky , after whom it sometimes is named .