Monday, 5 January 2015

Linguistic Premise Premise of Algebraic Linguistics 1-3 / September 17, 2007


Linguistic Premise

 Premise of Algebraic Linguistics 1-3

    TANAKA Akio

15
Definition of <presheaf>
Topological space     X
Arbitrary opened set     UV    U V
Commutative group     F  U )
Homomorphism     τUV :  V )   ( U )
Given conditions
(1)
F  ( 0 ) = { 0 }
(2)
τUV  = id    (Identity map)
(3)
U  V  W     τUW  =τUV oτVV
Presheaf of commutative ring on X     { F ( U ), τUV }

16
Definition of <sheaf>
Presheaf F, G  on X
Homomorphism     ψ :  G
Given conditions
(1)
Arbitrary opened set     U
Homomorphism     φ ( U ) : F ( U )  G ( U )
(2)
Opened sets     V
Below makes commutative diagram.
F ( V ) , G ( V ), F ( U ) , G ( U )
φ ( V ), φ.( U )
τUV,
(3)
F  U )  s
Open covering U
U i }∈ I r UiU = 0   ∈    s = 0
(4)
Open covering U
U i }∈ I
F ( U ) ∋ si     ∈ I
rUi Uj Ui (si ) = r Ui Uj (sj) (i, j  )    rUiU (s) = si ( i  )
Presheaf is sheaf.

Tokyo September 17, 2007
Sekinan Research Field of Language

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