Mikhail Belyaev

Here is a gdb backtrace if this helps: ``` (gdb) bt #0 0x00007ffff7c2eea0 in BitVector_equal () from /usr/lib/libstp.so.2.1 #1 0x00007ffff7be7f4b in stp::NonMemberBVConstEvaluator(stp::STPMgr*, stp::Kind, std::vector const&, unsigned int) () from /usr/lib/libstp.so.2.1...

Oh, I get it now. So `iff` instead of `=` for booleans, and, I guess `xor` instead of `!=`?) Anyway, it shouldn't crash with segfault, that's for sure. > Maybe...

`persistentList.map { it + 1 }.toPersistentList()` creates two intermediate objects instead of one. Also, in the particular case of `filter`, some persistent data structures can implement it in a persistent-friendly...