Nuprl Lemma : dm-neg-neg
∀[T:Type]. ∀[eq:EqDecider(T)]. ∀[x:Point(free-DeMorgan-lattice(T;eq))].
  (¬(¬(x)) = x ∈ Point(free-DeMorgan-lattice(T;eq)))
Proof
Definitions occuring in Statement : 
dm-neg: ¬(x), 
free-DeMorgan-lattice: free-DeMorgan-lattice(T;eq), 
lattice-point: Point(l), 
deq: EqDecider(T), 
uall: ∀[x:A]. B[x], 
universe: Type, 
equal: s = t ∈ T
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x], 
member: t ∈ T, 
all: ∀x:A. B[x], 
free-DeMorgan-lattice: free-DeMorgan-lattice(T;eq), 
subtype_rel: A ⊆r B, 
bdd-distributive-lattice: BoundedDistributiveLattice, 
so_lambda: λ2x.t[x], 
prop: ℙ, 
and: P ∧ Q, 
so_apply: x[s], 
uimplies: b supposing a, 
implies: P ⇒ Q, 
bounded-lattice-hom: Hom(l1;l2), 
lattice-hom: Hom(l1;l2), 
cand: A c∧ B, 
compose: f o g, 
dminc: <i>, 
dmopp: <1-i>, 
true: True, 
squash: ↓T, 
guard: {T}, 
iff: P ⇐⇒ Q, 
rev_implies: P ⇐ Q
Lemmas referenced : 
free-dist-lattice-hom-unique, 
union-deq_wf, 
free-DeMorgan-lattice_wf, 
free-dml-deq_wf, 
free-dl-inc_wf, 
lattice-point_wf, 
subtype_rel_set, 
bounded-lattice-structure_wf, 
lattice-structure_wf, 
lattice-axioms_wf, 
bounded-lattice-structure-subtype, 
bounded-lattice-axioms_wf, 
uall_wf, 
equal_wf, 
lattice-meet_wf, 
lattice-join_wf, 
deq_wf, 
free-dist-lattice_wf, 
lattice-0_wf, 
bdd-distributive-lattice_wf, 
lattice-1_wf, 
bdd-distributive-lattice-subtype-bdd-lattice, 
opposite-lattice_wf, 
compose-bounded-lattice-hom, 
bounded-lattice-hom_wf, 
dm-neg-is-hom, 
dm-neg-is-hom-opposite, 
dminc_wf, 
dmopp_wf, 
squash_wf, 
true_wf, 
dm-neg_wf, 
dm-neg-inc, 
iff_weakening_equal, 
dm-neg-opp
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation, 
introduction, 
cut, 
extract_by_obid, 
sqequalHypSubstitution, 
dependent_functionElimination, 
thin, 
unionEquality, 
cumulativity, 
hypothesisEquality, 
isectElimination, 
hypothesis, 
lambdaEquality, 
applyEquality, 
sqequalRule, 
instantiate, 
productEquality, 
universeEquality, 
because_Cache, 
independent_isectElimination, 
isect_memberEquality, 
axiomEquality, 
independent_functionElimination, 
applyLambdaEquality, 
setElimination, 
rename, 
equalitySymmetry, 
dependent_set_memberEquality, 
independent_pairFormation, 
productElimination, 
independent_pairEquality, 
equalityTransitivity, 
functionExtensionality, 
comment, 
unionElimination, 
natural_numberEquality, 
imageElimination, 
imageMemberEquality, 
baseClosed
Latex:
\mforall{}[T:Type].  \mforall{}[eq:EqDecider(T)].  \mforall{}[x:Point(free-DeMorgan-lattice(T;eq))].    (\mneg{}(\mneg{}(x))  =  x)
Date html generated:
2017_10_05-AM-00_41_59
Last ObjectModification:
2017_07_28-AM-09_16_56
Theory : lattices
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