Hello,TLC cannot enumerate infinite sets. A typical workaround for quantifier bounds involving infinite sets is to override a set such as Int by a small finite set such as -2 .. 2 if appropriate. (See "Additional Spec Options" -> "Definition Override").For the snippet shown in the message, I suggest that you avoid quantification altogether and write something likeServerResponse ==  /\ serverSt.status = "processing"  /\ serverSt' = [serverSt EXCEPT !.status = "idle"]  /\ msgs' = msgs \cup {[type |-> "response", to |-> serverSt.from, res |-> (serverSt.a + serverSt.b)]}  /\ UNCHANGED clientStNote that here the value of serverSt stays a record even when the status is "idle" so that the first conjunct makes sense (and evaluates to FALSE) even if the server is idle. You may want to reset the other record fields to default values so that TLC doesn't generate distinct states that differ only in values of irrelevant record fields.I believe that you can similarly rewrite the actions ServerReceive and ClientReceive. You still need quantification over integers in ClientSend for expressing non-determinism, and here you will have to use a finite set instead for model checking.Hope this helps,StephanOn 4 Feb 2020, at 13:09, abel.nieto90@xxxxxxxxx wrote:I'm getting started with TLA+ and wrote a spec for a simple server that adds two integers: https://pastebin.com/Yc8qfwa7When I run TLC, I get the following error:The exception was a java.lang.RuntimeException: TLC encountered a non-enumerable quantifier boundInt.line 46, col 34 to line 46, col 36 of module AdditionThe error occurred when TLC was evaluating the nestedexpressions at the following positions:0. Line 46, column 3 to line 50, column 27 in Addition1. Line 46, column 6 to line 49, column 84 in Addition The errors refers to a "non-enumerable quantifier bound Int", but Int is an enumerable set.The relevant snippet of my code readsServerResponse == \* server responds  /\ \E fromV \in CLIENT, aV \in Int, bV \in Int :       /\ serverSt = [status |-> "processing", from |-> fromV, a |-> aV, b |-> bV]       /\ serverSt' = "idle"       /\ msgs' = msgs \cup {[type |-> "response", to |-> fromV, res |-> (aV + bV)]}  /\ UNCHANGED <>What am I doing wrong here? And what's the idiomatic way to "deconstruct" records in TLA? Thanks!Abel -- You received this message because you are subscribed to the Google Groups "tlaplus" group. To unsubscribe from this group and stop receiving emails from it, send an email to tlaplus+unsubscribe@xxxxxxxxxxxxxxxx. To view this discussion on the web visit https://groups.google.com/d/msgid/tlaplus/2051d601-952a-434a-a93a-ebccb87843b9%40googlegroups.com. -- You received this message because you are subscribed to the Google Groups "tlaplus" group. To unsubscribe from this group and stop receiving emails from it, send an email to tlaplus+unsubscribe@xxxxxxxxxxxxxxxx. To view this discussion on the web visit https://groups.google.com/d/msgid/tlaplus/2A642E4C-42AA-40F4-B181-EFE289138E9E%40gmail.com.