# How to show equivalence of the Hoare assignment axiom vs Floyd assignment axiom?

I know from several sources that they are equivalent, but couldn't find a reasonable explanation. My first approach was to show their equivalence by using the logical consequence rule and both axioms, but I couldn't figure out a reasonable solution.

Here is the exact problem definition: Anybody can give me a hint how to show that both axioms are indeed equivalent?

• As a first step, try applying each axiom to obtain the other, i.e. for given $F$, apply the Hoare axiom to $G:=\exists v'(F[v/v']\wedge v=e[v/v'])$, and for given $G$, apply the Floyd axiom to $F:=G[v/e]$. Can you show that the resulting pre-/postcondition are equivalent to $F$ and $G$, respectively? – Klaus Draeger May 5 '15 at 17:52
• We prefer that you not use images for critical content of your post (e.g., the problem definition). This makes your question harder to search and inaccessible to the visually impaired; we don't like that. Please transcribe text and mathematics (note that you can use LaTeX). – D.W. May 6 '15 at 0:58