import algebra.ring

variables a b c : nat
variables H1 : a = b
variables H2 : b = c
set_option pp.all true

#app_builder eq.refl a
#app_builder eq.trans H1, H2
#app_builder eq.symm H1

open algebra nat
universe l
constant A : Type.{l}
constant s : comm_ring A
attribute s [instance]
variables x y : A

#app_builder eq.refl s
#app_builder eq.refl x
#app_builder add x, y
#app_builder add a, b
#app_builder mul a, b
#app_builder sub x, y