Section EQ_DEC.
#[global]
Instance ivar_hasEqDec : hasEqDec ivar :=
Nat.eq_dec.
Context {L : language}.
Hypothesis function_symbols_hasEqDec : hasEqDec L.(function_symbols).
Hypothesis constant_symbols_hasEqDec : hasEqDec L.(constant_symbols).

Lemma trm_eq_dec (t1 : trm L) (t2 : trm L)
: {t1 = t2} + {t1 <> t2}
with trms_eq_dec n (ts1 : trms L n) (ts2 : trms L n)
: {ts1 = ts2} + {ts1 <> ts2}.