Nuprl Lemma : q-square-positive
∀[q:ℚ]. 0 < q * q supposing ¬(q = 0 ∈ ℚ)
Proof
Definitions occuring in Statement : 
qless: r < s
, 
qmul: r * s
, 
rationals: ℚ
, 
uimplies: b supposing a
, 
uall: ∀[x:A]. B[x]
, 
not: ¬A
, 
natural_number: $n
, 
equal: s = t ∈ T
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x]
, 
member: t ∈ T
, 
uimplies: b supposing a
, 
subtype_rel: A ⊆r B
, 
implies: P 
⇒ Q
, 
prop: ℙ
, 
all: ∀x:A. B[x]
, 
iff: P 
⇐⇒ Q
, 
and: P ∧ Q
, 
or: P ∨ Q
, 
not: ¬A
, 
false: False
, 
rev_implies: P 
⇐ Q
Lemmas referenced : 
q-square-non-neg, 
qless_witness, 
qmul_wf, 
not_wf, 
equal_wf, 
rationals_wf, 
qle_iff_lt_or_eq_qorder, 
int-subtype-rationals, 
qmul-zero
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation, 
introduction, 
cut, 
lemma_by_obid, 
sqequalHypSubstitution, 
isectElimination, 
thin, 
hypothesisEquality, 
natural_numberEquality, 
hypothesis, 
applyEquality, 
because_Cache, 
sqequalRule, 
independent_functionElimination, 
isect_memberEquality, 
equalityTransitivity, 
equalitySymmetry, 
dependent_functionElimination, 
productElimination, 
unionElimination, 
voidElimination
Latex:
\mforall{}[q:\mBbbQ{}].  0  <  q  *  q  supposing  \mneg{}(q  =  0)
Date html generated:
2016_05_15-PM-10_59_02
Last ObjectModification:
2015_12_27-PM-07_51_06
Theory : rationals
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