Nuprl Definition : retraction
retraction(X;d;A) == {f:X ⟶ A| f:FUN(X;A) ∧ (∀a:A. f a ≡ a)}
Wellformedness Lemmas :
retraction_wf
Definitions occuring in Statement :
is-mfun: f:FUN(X;Y),
meq: x ≡ y,
all: ∀x:A. B[x],
and: P ∧ Q,
set: {x:A| B[x]} ,
apply: f a,
function: x:A ⟶ B[x]
Definitions occuring in definition :
apply: f a,
meq: x ≡ y,
all: ∀x:A. B[x],
is-mfun: f:FUN(X;Y),
and: P ∧ Q,
function: x:A ⟶ B[x],
set: {x:A| B[x]}
FDL editor aliases :
retraction
Latex:
retraction(X;d;A) == \{f:X {}\mrightarrow{} A| f:FUN(X;A) \mwedge{} (\mforall{}a:A. f a \mequiv{} a)\}
Date html generated:
2019_10_30-AM-06_36_27
Last ObjectModification:
2019_10_26-PM-00_00_09
Theory : reals
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