THM	zero_rank_all_vars	L:Sequent List. eqS:{Sequent=}. eqF:{Formula=}. sL.( s = 0) (hyp,concl:Formula List. <hyp, concl>(eqS) L (z:Formula z(eqF) hyp z(eqF) concl (v:Var. z = v)))
THM	zero_rank_valid_or_falsifiable	L:Sequent List sL.( s = 0) sL.|= s (a:Assignment. sL.a | s)
THM	prop_decide	S:Sequent. |= S (a:Assignment. a | S)
THM	propositional_decidability	S:Sequent. |= S (a:Assignment. a | S)

the other theories