===good============ mary.what2eat <- navel orange
YAP query succeed
prover success!!
credentials needed :
 pMary.what2eat  <- pRalphs.fruitprice(P:[..2.00]) 
 pRalphs.fruitprice(0.50)  <- 'navel orange' 
 
===good============ mary.what2eat <- kiwi
YAP query succeed
prover success!!
credentials needed :
 pMary.what2eat  <- pRalphs.fruitprice(P:[..2.00]) 
 pRalphs.fruitprice(1.50)  <- 'kiwi' 
 
===bad============ bob.what2eat <- navel orange
YAP query failed
prover failed!!
 
===good============ ralphs.fruitprice(1.50) <- apple
YAP query succeed
prover success!!
credentials needed :
 pRalphs.fruitprice(1.50)  <- 'apple' 
 
===bad============ ralphs.fruitprice(1.50) <- green apple
YAP query failed
prover failed!!