Nuprl Lemma : r2-det-is-dot-product
∀[a,b,c:ℝ^2].  (|abc| = a - b⋅λi.if (i =z 0) then -(c - b 1) else c - b 0 fi )
Proof
Definitions occuring in Statement : 
r2-det: |pqr|
, 
dot-product: x⋅y
, 
real-vec-sub: X - Y
, 
real-vec: ℝ^n
, 
req: x = y
, 
rminus: -(x)
, 
ifthenelse: if b then t else f fi 
, 
eq_int: (i =z j)
, 
uall: ∀[x:A]. B[x]
, 
apply: f a
, 
lambda: λx.A[x]
, 
natural_number: $n
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x]
, 
member: t ∈ T
, 
real-vec-sub: X - Y
, 
dot-product: x⋅y
, 
r2-det: |pqr|
, 
subtract: n - m
, 
nat: ℕ
, 
le: A ≤ B
, 
and: P ∧ Q
, 
less_than': less_than'(a;b)
, 
false: False
, 
not: ¬A
, 
implies: P 
⇒ Q
, 
prop: ℙ
, 
real-vec: ℝ^n
, 
int_seg: {i..j-}
, 
all: ∀x:A. B[x]
, 
bool: 𝔹
, 
unit: Unit
, 
it: ⋅
, 
btrue: tt
, 
ifthenelse: if b then t else f fi 
, 
uiff: uiff(P;Q)
, 
uimplies: b supposing a
, 
subtype_rel: A ⊆r B
, 
lelt: i ≤ j < k
, 
less_than: a < b
, 
squash: ↓T
, 
true: True
, 
bfalse: ff
, 
exists: ∃x:A. B[x]
, 
or: P ∨ Q
, 
sq_type: SQType(T)
, 
guard: {T}
, 
bnot: ¬bb
, 
assert: ↑b
, 
so_lambda: λ2x.t[x]
, 
decidable: Dec(P)
, 
satisfiable_int_formula: satisfiable_int_formula(fmla)
, 
top: Top
, 
so_apply: x[s]
, 
nequal: a ≠ b ∈ T 
, 
eq_int: (i =z j)
, 
itermConstant: "const"
, 
req_int_terms: t1 ≡ t2
, 
rev_uimplies: rev_uimplies(P;Q)
Lemmas referenced : 
req_witness, 
r2-det_wf, 
dot-product_wf, 
false_wf, 
le_wf, 
real-vec-sub_wf, 
eq_int_wf, 
bool_wf, 
eqtt_to_assert, 
assert_of_eq_int, 
rminus_wf, 
real-vec_wf, 
lelt_wf, 
eqff_to_assert, 
equal_wf, 
bool_cases_sqequal, 
subtype_base_sq, 
bool_subtype_base, 
assert-bnot, 
neg_assert_of_eq_int, 
int_seg_wf, 
rsub_wf, 
radd_wf, 
rmul_wf, 
rsum_wf, 
decidable__lt, 
satisfiable-full-omega-tt, 
intformand_wf, 
intformnot_wf, 
intformless_wf, 
itermVar_wf, 
itermConstant_wf, 
itermAdd_wf, 
int_formula_prop_and_lemma, 
int_formula_prop_not_lemma, 
int_formula_prop_less_lemma, 
int_term_value_var_lemma, 
int_term_value_constant_lemma, 
int_term_value_add_lemma, 
int_formula_prop_wf, 
intformeq_wf, 
int_formula_prop_eq_lemma, 
decidable__le, 
intformle_wf, 
int_formula_prop_le_lemma, 
equal-wf-base, 
int_subtype_base, 
real_term_polynomial, 
itermSubtract_wf, 
itermMultiply_wf, 
itermMinus_wf, 
int-to-real_wf, 
real_term_value_const_lemma, 
real_term_value_sub_lemma, 
real_term_value_add_lemma, 
real_term_value_mul_lemma, 
real_term_value_var_lemma, 
real_term_value_minus_lemma, 
req-iff-rsub-is-0, 
req_functionality, 
req_weakening, 
rsum-split-first, 
radd_functionality, 
rsum-single
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation, 
introduction, 
cut, 
sqequalRule, 
extract_by_obid, 
sqequalHypSubstitution, 
isectElimination, 
thin, 
hypothesisEquality, 
hypothesis, 
dependent_set_memberEquality, 
natural_numberEquality, 
independent_pairFormation, 
lambdaFormation, 
because_Cache, 
lambdaEquality, 
setElimination, 
rename, 
unionElimination, 
equalityElimination, 
productElimination, 
independent_isectElimination, 
applyEquality, 
imageMemberEquality, 
baseClosed, 
equalityTransitivity, 
equalitySymmetry, 
dependent_pairFormation, 
promote_hyp, 
dependent_functionElimination, 
instantiate, 
cumulativity, 
independent_functionElimination, 
voidElimination, 
isect_memberEquality, 
int_eqEquality, 
intEquality, 
voidEquality, 
computeAll, 
addEquality, 
setEquality
Latex:
\mforall{}[a,b,c:\mBbbR{}\^{}2].    (|abc|  =  a  -  b\mcdot{}\mlambda{}i.if  (i  =\msubz{}  0)  then  -(c  -  b  1)  else  c  -  b  0  fi  )
Date html generated:
2017_10_03-AM-11_40_36
Last ObjectModification:
2017_04_11-PM-05_29_09
Theory : reals
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