Logical connectives and quantifiers:

/\ conjunction \/ disjunction

=> implication <=> equivalence

~ negation

A for all E there exists

Predicates:

Triangle(x) x is a triangle Square(x) x is a square Pentagon(x) x is a pentagon Small(x) x is small Medium(x) x is medium Large(x) x is large

Smaller(x,y) x is smaller than y SameSize(x,y) x and y have the same size SameCol(x,y) x and y are in the same column SameRow(x,y) x and y are in the same row LeftOf(x,y) the column of x is on the left of the column of y Between(x,y,z) x is between y and z on a row, column or diagonal

Equality:

x = y	x is equal to y
x <> y	x is different from y

Variables: lowercase letters [a-z]

Disclaimer: This program was written by Dr. Robert F. Stärk and is available here with his permission. It was inspired by a similar and more sophisticated commercial program called Tarski's World published by CSLI at Stanford University. The Block World available from this page is not the product of CSLI. Dr. Stärk is not affiliated with CSLI.

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Last modified: 27-May-2007 / staerk@inf.ethz.ch