Nuprl Lemma : mdist-symm
∀[X:Type]. ∀[d:metric(X)]. ∀[x,y:X].  (mdist(d;x;y) = mdist(d;y;x))
Proof
Definitions occuring in Statement : 
mdist: mdist(d;x;y)
, 
metric: metric(X)
, 
req: x = y
, 
uall: ∀[x:A]. B[x]
, 
universe: Type
Definitions unfolded in proof : 
mdist: mdist(d;x;y)
, 
uall: ∀[x:A]. B[x]
, 
member: t ∈ T
, 
all: ∀x:A. B[x]
, 
metric: metric(X)
, 
implies: P 
⇒ Q
Lemmas referenced : 
metric-symmetry, 
req_witness, 
metric_wf, 
istype-universe
Rules used in proof : 
sqequalSubstitution, 
sqequalRule, 
sqequalReflexivity, 
sqequalTransitivity, 
computationStep, 
isect_memberFormation_alt, 
introduction, 
cut, 
extract_by_obid, 
sqequalHypSubstitution, 
isectElimination, 
thin, 
hypothesisEquality, 
dependent_functionElimination, 
hypothesis, 
applyEquality, 
setElimination, 
rename, 
because_Cache, 
independent_functionElimination, 
inhabitedIsType, 
isect_memberEquality_alt, 
isectIsTypeImplies, 
universeIsType, 
instantiate, 
universeEquality
Latex:
\mforall{}[X:Type].  \mforall{}[d:metric(X)].  \mforall{}[x,y:X].    (mdist(d;x;y)  =  mdist(d;y;x))
Date html generated:
2019_10_29-AM-10_57_56
Last ObjectModification:
2019_10_02-AM-09_39_45
Theory : reals
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