- Aren't programs simpler than logic formulas?
- Everyday mathematics simpler than programs.
- Assignment versus equality!
*Program*versus*mathematical*functions.

- Methods for reasoning about programs based on toy languages.
- Simpler than real programming languages.
- More complicated than simple logic.

- Resemblance often misleasing:
- { $x=0$ }
`y`:=`x`+1 { $y=x+1$ } `x`:=0;`y`:=`x`+1; write(`y`,`x`+1)- May be different in certain contexts (aliasing)!

- { $x=0$ }

Wolfgang.Schreiner@risc.uni-linz.ac.at

$$Id: tla1.tex,v 1.1 1996/04/29 08:36:08 schreine Exp schreine $$