TURING MACHINE

 The rule of the machine can be changed by clicking onto the matrix entries. Random produces a random machine. © 2000 Mathematik
 STEP STOP RUN CLEAR RANDOM
 A Turing machine can compute everything, a usual computer program can compute. Less efficient - but the computation allows a mathematical analysis of questions like :"What is computable? What is decidable? What is complexity? Input and output of a Turing machine is performed on a doubly infinite band containing 0 or 1's. This is the memory of the machine. The machine running here with 3 states does the following in state 2: if the band shows 0: go to state 3, move the band to the left and write 1. If the band shows 1, go to state 1, move the band to the left and write 0. This rule for state 2 can be abbreviated as 2: (3L1) (1L0). A challenging sport is to find among all Turing machines with n states the "busy beaver", the program, which produces from the empty band a maximum number of consecutive 1's before it halts.