Nuprl Lemma : ravg_comm
∀[x,y:ℝ].  (ravg(x;y) = ravg(y;x))
Proof
Definitions occuring in Statement : 
ravg: ravg(x;y), 
req: x = y, 
real: ℝ, 
uall: ∀[x:A]. B[x]
Definitions unfolded in proof : 
top: Top, 
not: ¬A, 
false: False, 
req_int_terms: t1 ≡ t2, 
rdiv: (x/y), 
true: True, 
less_than': less_than'(a;b), 
squash: ↓T, 
less_than: a < b, 
rev_uimplies: rev_uimplies(P;Q), 
uiff: uiff(P;Q), 
prop: ℙ, 
implies: P ⇒ Q, 
rev_implies: P ⇐ Q, 
and: P ∧ Q, 
iff: P ⇐⇒ Q, 
all: ∀x:A. B[x], 
or: P ∨ Q, 
guard: {T}, 
rneq: x ≠ y, 
uimplies: b supposing a, 
ravg: ravg(x;y), 
member: t ∈ T, 
uall: ∀[x:A]. B[x]
Lemmas referenced : 
real_term_value_const_lemma, 
real_term_value_var_lemma, 
real_term_value_add_lemma, 
real_term_value_mul_lemma, 
real_term_value_sub_lemma, 
real_polynomial_null, 
rmul-rinv3, 
radd_functionality, 
req_transitivity, 
req_functionality, 
req_weakening, 
req-iff-rsub-is-0, 
itermConstant_wf, 
itermVar_wf, 
itermAdd_wf, 
itermMultiply_wf, 
itermSubtract_wf, 
rinv_wf2, 
rless_wf, 
int-to-real_wf, 
radd_wf, 
rmul_wf, 
real_wf, 
ravg_wf, 
req_witness, 
rless-int, 
rdiv_wf, 
rmul_preserves_req
Rules used in proof : 
voidEquality, 
voidElimination, 
intEquality, 
int_eqEquality, 
lambdaEquality, 
approximateComputation, 
baseClosed, 
imageMemberEquality, 
independent_pairFormation, 
natural_numberEquality, 
isect_memberEquality, 
hypothesisEquality, 
independent_functionElimination, 
productElimination, 
dependent_functionElimination, 
inrFormation, 
hypothesis, 
sqequalRule, 
independent_isectElimination, 
because_Cache, 
thin, 
isectElimination, 
sqequalHypSubstitution, 
extract_by_obid, 
cut, 
introduction, 
isect_memberFormation, 
sqequalReflexivity, 
computationStep, 
sqequalTransitivity, 
sqequalSubstitution
Latex:
\mforall{}[x,y:\mBbbR{}].    (ravg(x;y)  =  ravg(y;x))
Date html generated:
2017_10_03-AM-08_41_44
Last ObjectModification:
2017_07_31-AM-10_31_17
Theory : reals
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