We prove that it is NP-hard to properly PAC learn decision trees with queries, resolving a longstanding open problem in learning theory (Bshouty 1993; Guijarro–Lavín–Raghavan 1999; Mehta–Raghavan 2002 ...

Finding the optimal Steiner Tree in graphs has been a critical combinatorial optimization challenge that finds widespread applications in network design. Despite its importance, finding the optimal ...