Set cardinality is a bigint, and we map it to CVC4's card

library/lang/Set.scala

src/main/java/leon/codegen/runtime/Set.java

src/main/scala/leon/codegen/CodeGeneration.scala

src/main/scala/leon/evaluators/RecursiveEvaluator.scala

src/main/scala/leon/frontends/scalac/CodeExtraction.scala

src/main/scala/leon/purescala/Expressions.scala

src/main/scala/leon/solvers/smtlib/SMTLIBCVC4Target.scala