def get_proof_term(self, t):
if not t.is_comb():
return refl(t)
f, c = t.fun, t.arg
if is_fun_upd(f):
f1, a, b = f.args
if a == c:
return rewr_conv("fun_upd_same").get_proof_term(t)
else:
neq = nat.nat_const_ineq(c, a)
eq = rewr_conv("fun_upd_other", conds=[neq]).get_proof_term(t)
return eq.on_arg(self)
elif f.is_abs():
return ProofTerm.beta_conv(t)
else:
return refl(t)
def rec(t):
if t.is_abs():
v, body = t.dest_abs()
body_pt = rec(body)
if body_pt.is_reflexive():
return refl(t)
else:
return body_pt.abstraction(v)
elif t.is_comb():
fun_pt = rec(t.fun)
arg_pt = rec(t.arg)
pt = fun_pt.combination(arg_pt)
if fun_pt.rhs.is_abs():
pt2 = ProofTerm.beta_conv(pt.rhs)
pt3 = rec(pt2.rhs)
return pt.transitive(pt2, pt3)
else:
return pt
else:
return refl(t)
def get_proof_term(self, t):
try:
return ProofTerm.beta_conv(t)
except InvalidDerivationException:
raise ConvException("beta_conv")
