Nuprl Lemma : r2-be-iff

∀u,v,x:ℝ^2.  (u_x_v ⇐⇒ ((¬(d(u;v) < d(u;x))) ∧ (¬(d(u;v) < d(x;v)))) ∧ (¬(r2-left(u;x;v) ∨ r2-left(u;v;x))))


Proof




Definitions occuring in Statement :  r2-left: r2-left(p;q;r),  rv-be: a_b_c,  real-vec-dist: d(x;y),  real-vec: ℝ^n,  rless: x < y,  all: ∀x:A. B[x],  iff: P ⇐⇒ Q,  not: ¬A,  or: P ∨ Q,  and: P ∧ Q,  natural_number: $n
Definitions unfolded in proof :  all: ∀x:A. B[x],  iff: P ⇐⇒ Q,  and: P ∧ Q,  implies: P ⇒ Q,  not: ¬A,  false: False,  uall: ∀[x:A]. B[x],  member: t ∈ T,  nat: ℕ,  le: A ≤ B,  less_than': less_than'(a;b),  subtype_rel: A ⊆r B,  prop: ℙ,  rev_implies: P ⇐ Q,  or: P ∨ Q,  uimplies: b supposing a,  guard: {T},  uiff: uiff(P;Q),  req_int_terms: t1 ≡ t2,  top: Top,  cand: A c∧ B,  stable: Stable{P},  rv-be: a_b_c,  real-vec-sep: a ≠ b

Latex:
\mforall{}u,v,x:\mBbbR{}\^{}2.
    (u\_x\_v  \mLeftarrow{}{}\mRightarrow{}  ((\mneg{}(d(u;v)  <  d(u;x)))  \mwedge{}  (\mneg{}(d(u;v)  <  d(x;v))))  \mwedge{}  (\mneg{}(r2-left(u;x;v)  \mvee{}  r2-left(u;v;x))))



Date html generated: 2020_05_20-PM-01_02_31
Last ObjectModification: 2019_12_11-PM-00_19_03

Theory : reals


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