Nuprl Lemma : face-one-and-zero
∀[X:j⊢]. ∀[z:{X ⊢ _:𝕀}].  (((z=1) ∧ (z=0)) = 0(𝔽) ∈ {X ⊢ _:𝔽})
Proof
Definitions occuring in Statement : 
face-zero: (i=0)
, 
face-one: (i=1)
, 
face-and: (a ∧ b)
, 
face-0: 0(𝔽)
, 
face-type: 𝔽
, 
interval-type: 𝕀
, 
cubical-term: {X ⊢ _:A}
, 
cubical_set: CubicalSet
, 
uall: ∀[x:A]. B[x]
, 
equal: s = t ∈ T
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x]
, 
member: t ∈ T
, 
uimplies: b supposing a
, 
face-0: 0(𝔽)
, 
face-zero: (i=0)
, 
face-one: (i=1)
, 
face-and: (a ∧ b)
, 
cubical-term-at: u(a)
, 
cubical-term: {X ⊢ _:A}
, 
subtype_rel: A ⊆r B
, 
cubical-type-at: A(a)
, 
pi1: fst(t)
, 
interval-type: 𝕀
, 
constant-cubical-type: (X)
, 
I_cube: A(I)
, 
functor-ob: ob(F)
, 
interval-presheaf: 𝕀
, 
lattice-point: Point(l)
, 
record-select: r.x
, 
dM: dM(I)
, 
free-DeMorgan-algebra: free-DeMorgan-algebra(T;eq)
, 
mk-DeMorgan-algebra: mk-DeMorgan-algebra(L;n)
, 
record-update: r[x := v]
, 
ifthenelse: if b then t else f fi 
, 
eq_atom: x =a y
, 
bfalse: ff
, 
free-DeMorgan-lattice: free-DeMorgan-lattice(T;eq)
, 
free-dist-lattice: free-dist-lattice(T; eq)
, 
mk-bounded-distributive-lattice: mk-bounded-distributive-lattice, 
mk-bounded-lattice: mk-bounded-lattice(T;m;j;z;o)
, 
btrue: tt
, 
bdd-distributive-lattice: BoundedDistributiveLattice
, 
so_lambda: λ2x.t[x]
, 
prop: ℙ
, 
and: P ∧ Q
, 
so_apply: x[s]
, 
face_lattice: face_lattice(I)
, 
face-lattice: face-lattice(T;eq)
, 
free-dist-lattice-with-constraints: free-dist-lattice-with-constraints(T;eq;x.Cs[x])
, 
constrained-antichain-lattice: constrained-antichain-lattice(T;eq;P)
, 
face-type: 𝔽
, 
face-presheaf: 𝔽
, 
true: True
, 
squash: ↓T
, 
all: ∀x:A. B[x]
, 
guard: {T}
, 
iff: P 
⇐⇒ Q
, 
rev_implies: P 
⇐ Q
, 
implies: P 
⇒ Q
Lemmas referenced : 
I_cube_wf, 
fset_wf, 
nat_wf, 
cubical-term-equal, 
face-type_wf, 
face-and_wf, 
face-one_wf, 
face-zero_wf, 
cubical-term_wf, 
interval-type_wf, 
cubical_set_wf, 
cubical-type-at_wf_face-type, 
subtype_rel_self, 
lattice-point_wf, 
free-DeMorgan-lattice_wf, 
names_wf, 
names-deq_wf, 
subtype_rel_set, 
bounded-lattice-structure_wf, 
lattice-structure_wf, 
lattice-axioms_wf, 
bounded-lattice-structure-subtype, 
bounded-lattice-axioms_wf, 
equal_wf, 
lattice-meet_wf, 
lattice-join_wf, 
lattice-0_wf, 
face_lattice_wf, 
squash_wf, 
true_wf, 
istype-universe, 
dM-to-FL-neg, 
iff_weakening_equal
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation_alt, 
introduction, 
cut, 
functionExtensionality, 
extract_by_obid, 
sqequalHypSubstitution, 
isectElimination, 
thin, 
hypothesisEquality, 
hypothesis, 
equalityTransitivity, 
equalitySymmetry, 
independent_isectElimination, 
universeIsType, 
instantiate, 
sqequalRule, 
isect_memberEquality_alt, 
axiomEquality, 
isectIsTypeImplies, 
inhabitedIsType, 
Error :memTop, 
applyEquality, 
setElimination, 
rename, 
lambdaEquality_alt, 
productEquality, 
cumulativity, 
isectEquality, 
because_Cache, 
natural_numberEquality, 
imageElimination, 
universeEquality, 
dependent_functionElimination, 
imageMemberEquality, 
baseClosed, 
productElimination, 
independent_functionElimination
Latex:
\mforall{}[X:j\mvdash{}].  \mforall{}[z:\{X  \mvdash{}  \_:\mBbbI{}\}].    (((z=1)  \mwedge{}  (z=0))  =  0(\mBbbF{}))
Date html generated:
2020_05_20-PM-02_43_14
Last ObjectModification:
2020_04_04-PM-04_57_17
Theory : cubical!type!theory
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