Proof

$\displaystyle (x > -10) \to$   True $\displaystyle , (y \geq 0) \to (y \geq -5)$

is True , so we use weakening:

$\displaystyle \frac{(x > -10) \to \mbox{true}, (y \geq 0) \to (y \geq -5), \lan...
...0 \rangle }{\langle x > -10 \rangle \; y := x^2 \; \langle y \geq -5 \rangle } $



David Goodwin 2008-09-20