[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

*From*: mlj...@xxxxxxxxx*Date*: Tue, 16 Jan 2018 11:43:44 -0800 (PST)

Hi guys, I've met some problems of function definitions. For instance, in math, I've got two sets A and B; and I'd like to define a partial function f as A -|-> B. Also, I want to define an operation that adding an element to the set, like f' = f \cup {(a, b)}, where a \in A and b \in B. So in TLA+, I tried to write the spec like: CONSTANT A, B VARIABLES f TypeOK == f \subseteq [A -> B] Init == f = {} Add(a, b) == f' = f \cup {[a |-> b]} Next == \E a \in A, b \in B : Add(a, b) However, I got errors when running model checking in TLC. It seems that it treats [a |-> b] as a record. But my purpose is to add a tuple of (a, b) to the function f, where f should be a set of tuples as it defined in math, like {(a1, b1), (a2, b2)}. So how can I write it in TLA+? Best Regards, Changjian Zhang

**Follow-Ups**:

- Prev by Date:
**Re: [tlaplus] Confusion on "invariant under stuttering"** - Next by Date:
**Re: How to define a partial function and add an element to a set of functions in TLA+?** - Previous by thread:
**Re: [tlaplus] Confusion on "invariant under stuttering"** - Next by thread:
**Re: How to define a partial function and add an element to a set of functions in TLA+?** - Index(es):