| ⊦ step(s, a, s0) ∧ ¬ cod(cren)(ren(a)) → repla(step, cstep, cren, ren, aren, cext, aext, (s, cs) ' + (s0, cs) ' + pcsl, ren(a) ' + pal, ⌜as '⌝ + aσ, aα) = ren(a) ' + repla(step, cstep, cren, ren, aren, cext, aext, (s0, cs) ' + pcsl, pal, ⌜as '⌝ + aσ, aα) |