lemma1 : {c10 :@$\mathbb{N}$@} @$\rightarrow$@ Axiom (stmt1Cond {c10}) (@$\lambda$@ env @$\rightarrow$@ record { varn = varn env ; vari = 0 }) (stmt2Cond {c\
10})
lemma1 {c10} env = impl@$\Rightarrow$@ ( @$\lambda$@ cond @$\rightarrow$@ let open @$\equiv$@-Reasoning  in
begin
(Equal (varn env) c10 ) @$\wedge$@ true
@$\equiv$@@$\langle$@ @$\wedge$@true @$\rangle$@
Equal (varn env) c10
@$\equiv$@@$\langle$@ cond @$\rangle$@
true
@$\blacksquare$@ )