User blog comment:P進大好きbot/Proposal to Choose an Official Standard OCF in This Wiki/@comment-37485018-20191221014123/@comment-35470197-20191221233123

You need additional conditions. For exameple, \(C_0(\psi_3(0))\) does not contain \(\psi_0(\psi_2(\psi_3(0)))\) although \(\psi_2(\psi_3(0))\) is smaller than \(\psi_3(0)\).