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*From*: Markus Kuppe <tlaplus-google-group@xxxxxxxxxxx>*Date*: Mon, 28 Jun 2021 12:33:14 -0700*References*: <16569f5a-d5fe-01d9-196a-c5e76adaaaed@shuhaowu.com>

On 6/28/21 12:01 PM, Shuhao Wu wrote:

I've been trying to write a temporal property to check in TLC where Iwant to know that some condition F leads to G, and G remain true for therest of time. This lead me to using the temporal operators ~> and []together, in a statement in the form of F ~> []G. I'm likelymisunderstanding one of these operators, as when I used TLC to check thefollowing simple spec, the nothing was found to be violated:--fair algorithm leadstoalways variables i = 1; define \* This is the temporal property to check OneLeadsToTwo == (i = 1) ~> [](i = 2) end define; begin step1: i := 2; step2: i := 3; step3: i := 2; end algorithm;My understanding is that (i = 1) ~> (i = 2) would be true for the aboveprogram (which is true in TLC). In the same understanding, (i = 1) ~>[](i = 2) would not be true, as the variable i changed from 1 to 2, thenaway from 2, and then back to 2. This means that i = 2 is not alwaystrue following the initial transition from i = 1 to i = 2.What am I missing?

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