Nuprl Lemma : Game-minus-minus
∀G:Game. -(-(G)) ≡ G
Proof
Definitions occuring in Statement : 
eq-Game: G ≡ H, 
Game-minus: -(G), 
Game: Game, 
all: ∀x:A. B[x]
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x], 
so_lambda: λ2x.t[x], 
member: t ∈ T, 
prop: ℙ, 
so_apply: x[s], 
implies: P ⇒ Q, 
all: ∀x:A. B[x], 
or: P ∨ Q, 
guard: {T}, 
eq-Game: G ≡ H, 
and: P ∧ Q, 
Game-minus: -(G), 
right-move: right-move(g;x), 
left-move: left-move(g;x), 
left-indices: left-indices(g), 
right-indices: right-indices(g), 
mkGame: {mkGame(f[a] with a:L | g[b] with b:R}, 
Wsup: Wsup(a;b), 
pi1: fst(t), 
pi2: snd(t), 
cand: A c∧ B, 
exists: ∃x:A. B[x], 
right-option: right-option{i:l}(g;m), 
left-option: left-option{i:l}(g;m)
Lemmas referenced : 
Game-induction, 
eq-Game_wf, 
Game-minus_wf, 
Game_wf, 
left-option_wf, 
right-option_wf, 
left-move_wf, 
right-indices_wf, 
right-move_wf, 
left-indices_wf, 
eq-Game_inversion
Rules used in proof : 
cut, 
introduction, 
extract_by_obid, 
sqequalHypSubstitution, 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isectElimination, 
thin, 
sqequalRule, 
lambdaEquality_alt, 
cumulativity, 
hypothesisEquality, 
hypothesis, 
universeIsType, 
independent_functionElimination, 
lambdaFormation_alt, 
functionIsType, 
inhabitedIsType, 
unionIsType, 
independent_pairFormation, 
dependent_pairFormation_alt, 
dependent_functionElimination, 
inlFormation_alt, 
equalityIstype, 
productIsType, 
inrFormation_alt, 
because_Cache
Latex:
\mforall{}G:Game.  -(-(G))  \mequiv{}  G
Date html generated:
2019_10_31-AM-06_35_13
Last ObjectModification:
2019_09_12-PM-01_28_11
Theory : Numbers!and!Games
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