Nuprl Lemma : psub_weakening
∀a,b:formula().  a ⊆ b supposing a = b ∈ formula()
Proof
Definitions occuring in Statement : 
psub: a ⊆ b
, 
formula: formula()
, 
uimplies: b supposing a
, 
all: ∀x:A. B[x]
, 
equal: s = t ∈ T
Definitions unfolded in proof : 
all: ∀x:A. B[x]
, 
uall: ∀[x:A]. B[x]
, 
so_lambda: λ2x.t[x]
, 
member: t ∈ T
, 
uimplies: b supposing a
, 
prop: ℙ
, 
so_apply: x[s]
, 
implies: P 
⇒ Q
, 
psub: a ⊆ b
, 
pvar: pvar(name)
, 
formula_ind: formula_ind, 
subtype_rel: A ⊆r B
, 
pnot: pnot(sub)
, 
or: P ∨ Q
, 
pand: pand(left;right)
, 
por: por(left;right)
, 
pimp: pimp(left;right)
, 
guard: {T}
Lemmas referenced : 
formula-induction, 
isect_wf, 
equal_wf, 
formula_wf, 
psub_wf, 
equal-wf-T-base, 
atom_subtype_base, 
pnot_wf, 
or_wf, 
pand_wf, 
por_wf, 
pimp_wf
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
lambdaFormation, 
cut, 
introduction, 
extract_by_obid, 
sqequalHypSubstitution, 
isectElimination, 
thin, 
sqequalRule, 
lambdaEquality, 
hypothesis, 
hypothesisEquality, 
independent_functionElimination, 
isect_memberFormation, 
baseApply, 
closedConclusion, 
baseClosed, 
applyEquality, 
atomEquality, 
axiomEquality, 
rename, 
inlFormation, 
because_Cache
Latex:
\mforall{}a,b:formula().    a  \msubseteq{}  b  supposing  a  =  b
Date html generated:
2018_05_21-PM-08_52_49
Last ObjectModification:
2017_07_26-PM-06_16_05
Theory : general
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