Nuprl Definition : win2strat

strategy that allows player two to respond to plays by player one.
Anything is such strategy for n=0.
For 0 < n, the strategy must also work for n-1, and for any play of the
game of length 2*n that has followed that strategy, the strategy
gives legal move for player two that extends that play.⋅

win2strat(g;n) ==
  if (n =z 0)
  then Top
  else s:win2strat(g;n 1) ⋂ moves:{f:strat2play(g;n 1;s)| ||f|| (2 n) ∈ ℤ}  ⟶ {p:Pos(g)| Legal2(moves[(2 n) -\000C 1];p)} 
  fi 



Definitions occuring in Statement :  play-len: ||moves|| play-item: moves[i] sg-legal2: Legal2(x;y) sg-pos: Pos(g) dep-isect: x:A ⋂ B[x] ifthenelse: if then else fi  eq_int: (i =z j) top: Top set: {x:A| B[x]}  function: x:A ⟶ B[x] multiply: m subtract: m natural_number: $n int: equal: t ∈ T
Definitions occuring in definition :  ifthenelse: if then else fi  eq_int: (i =z j) top: Top dep-isect: x:A ⋂ B[x] function: x:A ⟶ B[x] equal: t ∈ T int: play-len: ||moves|| set: {x:A| B[x]}  sg-pos: Pos(g) sg-legal2: Legal2(x;y) play-item: moves[i] subtract: m multiply: m natural_number: $n
FDL editor aliases :  win2strat

Latex:
win2strat(g;n)  ==
    if  (n  =\msubz{}  0)
    then  Top
    else  s:win2strat(g;n  -  1)  \mcap{}  moves:\{f:strat2play(g;n  -  1;s)|  ||f||  =  (2  *  n)\}    {}\mrightarrow{}  \{p:Pos(g)|  Legal2\000C(moves[(2  *  n)  -  1];p)\} 
    fi 



Date html generated: 2018_07_25-PM-01_31_33
Last ObjectModification: 2018_07_11-PM-11_01_38

Theory : co-recursion


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