>>850

# PならばQ ≡　(P かつ (Qでない))ではない
'%=>%' = function(P,Q) !(P & !Q)

> gr=expand.grid(c(T,F),c(T,F),c(T,F))
> colnames(gr)=c('rain','wind','thunder')
> f1 = function(rain, wind,thunder) rain %=>% (wind & thunder)
> f2 = function(rain, wind,thunder) (!wind & !thunder) %=>% !rain
> f3 = function(rain, wind,thunder) !wind %=>% !rain
> data.frame(gr,f1=mapply(f1,gr[,1],gr[,2],gr[,3]),
+ f2=mapply(f2,gr[,1],gr[,2],gr[,3]),
+ f3=mapply(f1,gr[,1],gr[,2],gr[,3]))

rain wind thunder f1 f2 f3
1 TRUE TRUE TRUE TRUE TRUE TRUE
2 FALSE TRUE TRUE TRUE TRUE TRUE
3 TRUE FALSE TRUE FALSE TRUE FALSE
4 FALSE FALSE TRUE TRUE TRUE TRUE
5 TRUE TRUE FALSE FALSE TRUE FALSE
6 FALSE TRUE FALSE TRUE TRUE TRUE
7 TRUE FALSE FALSE FALSE FALSE FALSE
8 FALSE FALSE FALSE TRUE TRUE TRUE