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Delegate kSubset semantics to KSubsetValue #130

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Merged
lemmy merged 1 commit into from
Sep 12, 2026
Merged

Delegate kSubset semantics to KSubsetValue #130

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20 changes: 7 additions & 13 deletions modules/tlc2/overrides/FiniteSetsExt.java
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Original file line number Diff line number Diff line change
Expand Up @@ -38,7 +38,7 @@
import tlc2.value.impl.KSubsetValue;
import tlc2.value.impl.OpValue;
import tlc2.value.impl.SetEnumValue;
import tlc2.value.impl.SubsetValue;
import tlc2.value.impl.UserValue;
import tlc2.value.impl.Value;
import tlc2.value.impl.ValueEnumeration;

Expand Down Expand Up @@ -77,23 +77,17 @@ public static Value quantify(final Value set, final OpValue test) {
}

@TLAPlusOperator(identifier = "kSubset", module = "FiniteSetsExt", warn = false)
public static Value kSubset(final Value kv, final Value s) {
final SetEnumValue set = (SetEnumValue) s.toSetEnum();
if (set == null) {
throw new EvalException(EC.TLC_MODULE_ARGUMENT_ERROR,
new String[] { "second", "kSubset", "set", Values.ppr(s.toString()) });
}
public static Value kSubset(final Value kv, final Value set) {
if (!(kv instanceof IntValue)) {
throw new EvalException(EC.TLC_MODULE_ARGUMENT_ERROR,
new String[] { "first", "kSubset", "natural number", Values.ppr(kv.toString()) });
}
final int k = ((IntValue) kv).val;

if (k < 0 || set.size() < k) {
return SetEnumValue.EmptySet;
}
if (k == 0) {
return new SubsetValue(SetEnumValue.EmptySet);

// Reject non-sets such as 42, TRUE, "foo", <<1>>, [a |-> 1], [x \in {1} |-> x], and model values.
if (!(set instanceof Enumerable || set instanceof UserValue)) {
throw new EvalException(EC.TLC_MODULE_ARGUMENT_ERROR,
new String[] { "second", "kSubset", "set", Values.ppr(set.toString()) });
}
return new KSubsetValue(k, set, set.cm);
}
Expand Down
23 changes: 0 additions & 23 deletions tests/FiniteSetsExtTests.tla
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Original file line number Diff line number Diff line change
Expand Up @@ -29,29 +29,6 @@ ASSUME LET S == 1..2000000

-----------------------------------------------------------------------------

ASSUME LET S == {"a","b","c","c"} \* Make sure value normalization works.
IN \A k \in -1..Cardinality(S) + 1:
kSubset(k, S) = {s \in SUBSET S : Cardinality(s) = k}

ASSUME LET S == {"a","b","c","c"} \* Make sure value normalization works.
IN kSubset(-1, S) = {} /\ kSubset(4, S) = {}

\* The commented variant takes my computer ~30 seconds, whereas the kSubset
\* variant finishes in under 1s.
\*ASSUME LET S == 1..27
\* IN {s \in SUBSET S : Cardinality(s) = Cardinality(S)} = {S}
ASSUME LET S == 1..27
IN kSubset(Cardinality(S), S) = {S}

ASSUME {} \notin kSubset(1, {1,2,3})

ASSUME LET T == 1..3
IN \A k \in (1..Cardinality(T)):
/\ \A e \in { ss \in (SUBSET T) : Cardinality(ss) = k} :
e \in kSubset(k, T)
/\ \A e \in { ss \in (SUBSET T) : Cardinality(ss) # k} :
e \notin kSubset(k, T)

ASSUME LET T == {"a","b","c"}
kSubsetPure(k, S) == { s \in SUBSET S : Cardinality(s) = k }
IN \A k \in 1..Cardinality(T):
Expand Down
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