On the toggling-branching recurrence of Computability Logic
  We introduce a new, substantially simplified version of the toggling-branching recurrence operation of Computability Logic, prove its equivalence to Japaridze's old, "canonical" version, and also prove that both versions preserve the static property of their arguments. 
Meixia Qu, Junfeng Luan, Daming Zhu
cs.LO