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agda-spa/lean/Spa/Analysis/Forward/Lattices.lean
Danila Fedorin e2df847139 Adopt lemma as the default keyword
Convert every theorem to lemma (mathlib's default) except the headline results a
reader of each module seeks out: analyze_correct (Forward/Sign/Constant),
aFix_eq/aFix_le (Fixedpoint), trace (Language), and Stmt.cfg_sufficient
(Language/Properties). lemma and theorem are interchangeable keywords, so no
references change.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
2026-06-25 14:08:10 -05:00

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import Spa.Language
import Spa.Lattice.FiniteMap
import Spa.Interp
namespace Spa
namespace Forward
variable (L : Type) [Lattice L] (prog : Program)
abbrev VariableValues : Type := FiniteMap String L prog.vars
abbrev StateVariables : Type := FiniteMap prog.State (VariableValues L prog) prog.states
def botV [FiniteHeightLattice L] : VariableValues L prog :=
( : VariableValues L prog)
variable {L prog}
omit [Lattice L] in
lemma states_memKey (s : prog.State) (sv : StateVariables L prog) :
FiniteMap.MemKey s sv :=
FiniteMap.MemKey_iff.mpr (prog.states_complete s)
def variablesAt (s : prog.State) (sv : StateVariables L prog) :
VariableValues L prog :=
(FiniteMap.locate (states_memKey s sv)).1
omit [Lattice L] in
lemma variablesAt_mem (s : prog.State) (sv : StateVariables L prog) :
(s, variablesAt s sv) sv :=
(FiniteMap.locate (states_memKey s sv)).2
lemma variablesAt_le {sv₁ sv₂ : StateVariables L prog} (hle : sv₁ sv₂)
(s : prog.State) : variablesAt s sv₁ variablesAt s sv₂ :=
FiniteMap.le_of_mem_mem prog.states_nodup hle
(variablesAt_mem s sv₁) (variablesAt_mem s sv₂)
variable [FiniteHeightLattice L]
def joinForKey (k : prog.State) (sv : StateVariables L prog) :
VariableValues L prog :=
(sv.valuesAt (prog.incoming k)).foldr (· ·) (botV L prog)
lemma joinForKey_mono (k : prog.State) :
Monotone (joinForKey (L := L) k) := by
intro sv₁ sv₂ hle
exact foldr_mono _ (FiniteMap.valuesAt_le hle (prog.incoming k)) (le_refl _)
(fun b _ _ hab => sup_le_sup_right hab b)
(fun a _ _ hab => sup_le_sup_left hab a)
def joinAll (sv : StateVariables L prog) : StateVariables L prog :=
FiniteMap.generalizedUpdate id joinForKey prog.states sv
lemma joinAll_mono : Monotone (joinAll (L := L) (prog := prog)) :=
FiniteMap.generalizedUpdate_monotone monotone_id joinForKey_mono
lemma joinAll_mem_eq {s : prog.State} {vs : VariableValues L prog}
{sv : StateVariables L prog} (h : (s, vs) joinAll sv) :
vs = joinForKey s sv :=
FiniteMap.generalizedUpdate_mem_eq (prog.states_complete s) h
lemma variablesAt_joinAll (s : prog.State) (sv : StateVariables L prog) :
variablesAt s (joinAll sv) = joinForKey s sv :=
joinAll_mem_eq (variablesAt_mem s (joinAll sv))
/-! ### Lifting an interpretation to variable maps -/
variable [I : LatticeInterpretation L]
omit [FiniteHeightLattice L] in
instance : Interp (VariableValues L prog) (Env Prop) where
interp (vs : VariableValues L prog) (ρ : Env) : Prop :=
(k : String) (l : L), (k, l) vs
(v : Value), Env.Mem (k, v) ρ I.interp l v
lemma interp_botV_nil : botV L prog [] := by
intro k l _ v hmem
cases hmem
omit [FiniteHeightLattice L] in
lemma interp_sup {vs₁ vs₂ : VariableValues L prog} {ρ : Env}
(h : vs₁ ρ vs₂ ρ) : vs₁ vs₂ ρ := by
intro k l hmem v hv
obtain l₁, l₂, rfl, h₁, h₂ := FiniteMap.mem_sup hmem
rcases h with h | h
· exact I.interp_sup v (Or.inl (h _ _ h₁ _ hv))
· exact I.interp_sup v (Or.inr (h _ _ h₂ _ hv))
lemma interp_foldr {vs : VariableValues L prog}
{vss : List (VariableValues L prog)} {ρ : Env}
(hvs : vs ρ) (hmem : vs vss) :
vss.foldr (· ·) (botV L prog) ρ := by
induction vss with
| nil => cases hmem
| cons vs' vss' ih =>
rcases List.mem_cons.mp hmem with rfl | hmem'
· exact interp_sup (Or.inl hvs)
· exact interp_sup (Or.inr (ih hmem'))
end Forward
end Spa