let zero = Listx.Nil zero in
let args = if n = 0 then zero else Listx.append zero (Listx.from_list vars) in
let bs = ref [] in
let zero = Listx.Nil zero in
let args = if n = 0 then zero else Listx.append zero (Listx.from_list vars) in
let bs = ref [] in
let inst = `Lam(false,arity1,`Match(`I(0,Listx.map (lift 1) args),arity2,1,bs,[])) in
let p = {p with deltas=bs::p.deltas} in
subst_in_problem x inst p
let inst = `Lam(false,arity1,`Match(`I(0,Listx.map (lift 1) args),arity2,1,bs,[])) in
let p = {p with deltas=bs::p.deltas} in
subst_in_problem x inst p