diff --git a/src/ir/opt/mem/ram/checker.rs b/src/ir/opt/mem/ram/checker.rs
index c74f5b16..d6d93c49 100644
--- a/src/ir/opt/mem/ram/checker.rs
+++ b/src/ir/opt/mem/ram/checker.rs
@@ -304,7 +304,7 @@ fn derivative_gcd(
     let pairs = term(
         Op::Array(Box::new(ArrayOp {
             key: fs.clone(),
-            val: Sort::Tuple(Box::new([fs.clone(), Sort::Bool])),
+            val: Sort::new_tuple(vec![fs.clone(), Sort::Bool]),
         })),
         values
             .clone()
diff --git a/src/ir/term/dist.rs b/src/ir/term/dist.rs
index c271a8dd..002d53da 100644
--- a/src/ir/term/dist.rs
+++ b/src/ir/term/dist.rs
@@ -176,11 +176,12 @@ impl FixedSizeDist {
         match op {
             Op::Ite => vec![Sort::Bool, sort.clone(), sort.clone()],
             o if o.arity() == Some(0) => vec![],
-            Op::Field(i) => vec![if let Sort::Tuple(mut ss) =
+            Op::Field(i) => vec![if let Sort::Tuple(ss) =
                 self.sample_tuple_sort(*i + 1, self.size - 1, rng)
             {
+                let mut ss = (*ss).to_vec();
                 ss[*i] = sort.clone();
-                Sort::Tuple(ss)
+                Sort::new_tuple(ss)
             } else {
                 unreachable!()
             }],
diff --git a/src/ir/term/ext/poly.rs b/src/ir/term/ext/poly.rs
index a48daee9..8312efc6 100644
--- a/src/ir/term/ext/poly.rs
+++ b/src/ir/term/ext/poly.rs
@@ -23,7 +23,7 @@ pub fn check(arg_sorts: &[&Sort]) -> Result<Sort, TypeErrorReason> {
                 "UniqDeriGcd pairs: second element must be a bool",
             )?;
             let arr = Sort::new_array(f.clone(), f.clone(), size);
-            Ok(Sort::Tuple(Box::new([arr.clone(), arr])))
+            Ok(Sort::new_tuple(vec![arr.clone(), arr]))
         } else {
             // non-pair entries value
             Err(TypeErrorReason::Custom(
diff --git a/src/ir/term/ext/ram.rs b/src/ir/term/ext/ram.rs
index d085b1ca..e7e7612e 100644
--- a/src/ir/term/ext/ram.rs
+++ b/src/ir/term/ext/ram.rs
@@ -14,14 +14,14 @@ pub fn check(arg_sorts: &[&Sort]) -> Result<Sort, TypeErrorReason> {
     let f = pf_or(i_value, "PersistentRamSplit indices")?;
     let n_touched = i_size.min(size);
     let n_ignored = size - n_touched;
-    let f_pair = Sort::Tuple(Box::new([f.clone(), f.clone()]));
+    let f_pair = Sort::new_tuple(vec![f.clone(), f.clone()]);
     let ignored_entries_sort = Sort::Tuple(vec![f_pair.clone(); n_ignored].into());
     let selected_entries_sort = Sort::Tuple(vec![f_pair.clone(); n_touched].into());
-    Ok(Sort::Tuple(Box::new([
+    Ok(Sort::new_tuple(vec![
         ignored_entries_sort,
         selected_entries_sort.clone(),
         selected_entries_sort,
-    ])))
+    ]))
 }
 
 /// Evaluate [super::ExtOp::PersistentRamSplit].
diff --git a/src/ir/term/mod.rs b/src/ir/term/mod.rs
index edf958d4..06c6aa8d 100644
--- a/src/ir/term/mod.rs
+++ b/src/ir/term/mod.rs
@@ -31,6 +31,7 @@ use serde::{Deserialize, Deserializer, Serialize, Serializer};
 use std::borrow::Borrow;
 use std::cell::Cell;
 use std::collections::BTreeMap;
+use std::sync::Arc;
 
 pub mod bv;
 pub mod dist;
@@ -798,11 +799,11 @@ pub enum Sort {
     /// Array from one sort to another, of fixed size.
     ///
     /// size presumes an order, and a zero, for the key sort.
-    Array(Box<ArraySort>),
+    Array(Arc<ArraySort>),
     /// Map from one sort to another.
-    Map(Box<MapSort>),
+    Map(Arc<MapSort>),
     /// A tuple
-    Tuple(Box<[Sort]>),
+    Tuple(Arc<[Sort]>),
 }
 
 #[derive(Clone, PartialEq, Eq, Hash, PartialOrd, Ord, Serialize, Deserialize)]
@@ -872,6 +873,11 @@ impl Sort {
         }
     }
 
+    /// Create a new tuple sort
+    pub fn new_tuple(sorts: Vec<Sort>) -> Self {
+        Self::Tuple(Arc::from(sorts.into_boxed_slice()))
+    }
+
     #[track_caller]
     /// Unwrap the constituent sorts of this array, panicking otherwise.
     pub fn as_array(&self) -> (&Sort, &Sort, usize) {
@@ -884,7 +890,7 @@ impl Sort {
 
     /// Create a new array sort
     pub fn new_array(key: Sort, val: Sort, size: usize) -> Self {
-        Self::Array(Box::new(ArraySort { key, val, size }))
+        Self::Array(Arc::new(ArraySort { key, val, size }))
     }
 
     /// Is this an array?
@@ -909,7 +915,7 @@ impl Sort {
 
     /// Create a new map sort
     pub fn new_map(key: Sort, val: Sort) -> Self {
-        Self::Map(Box::new(MapSort { key, val }))
+        Self::Map(Arc::new(MapSort { key, val }))
     }
 
     /// The nth element of this sort.
diff --git a/src/target/smt/mod.rs b/src/target/smt/mod.rs
index 579d5cbc..3ff4a658 100644
--- a/src/target/smt/mod.rs
+++ b/src/target/smt/mod.rs
@@ -538,7 +538,7 @@ mod test {
     fn tuple_is_sat() {
         let t = term![Op::Eq; term![Op::Field(0); term![Op::Tuple; bv_lit(0,4), bv_lit(5,6)]], var("a".into(), Sort::BitVector(4))];
         assert!(check_sat(&t));
-        let t = term![Op::Eq; term![Op::Tuple; bv_lit(0,4), bv_lit(5,6)], var("a".into(), Sort::Tuple(vec![Sort::BitVector(4), Sort::BitVector(6)].into_boxed_slice()))];
+        let t = term![Op::Eq; term![Op::Tuple; bv_lit(0,4), bv_lit(5,6)], var("a".into(), Sort::new_tuple(vec![Sort::BitVector(4), Sort::BitVector(6)]))];
         assert!(check_sat(&t));
     }