| ⊦ ( (ctrok(gs.ctr, gs.writers) ∧ writersOk(gs.p, gs.writers) ∧ pendingOk(gs.p)) ∧ notMember(ls.t, gs.writers) ∧ notMember(ls.t, gs.readers) ∧ noPendingW(ls.t, gs.p)) ∧ pre(gs, ls, R1, a) ∧ pcstepf(gs, ls, R1, a) = R2 → ( ctrok(gstepf(gs, ls, R1, a).ctr, gstepf(gs, ls, R1, a).writers) ∧ writersOk(gstepf(gs, ls, R1, a).p, gstepf(gs, ls, R1, a).writers) ∧ pendingOk(gstepf(gs, ls, R1, a).p)) ∧ notMember(lstepf(gs, ls, R1, a).t, gstepf(gs, ls, R1, a).writers) ∧ oneMember(lstepf(gs, ls, R1, a).t, lstepf(gs, ls, R1, a).l, gstepf(gs, ls, R1, a).readers) ∧ noPendingW(lstepf(gs, ls, R1, a).t, gstepf(gs, ls, R1, a).p) |