# Thread: State conditions - correct syntax

1. ## State conditions - correct syntax

Hello

First of all thank you so much to founders of this forum and all the members who reply to questions ...

sometimes system state is represented as a triple: first state Q1, action, final state Q2.

we have:
Q1={A, B}
where A={1,2,3}

action=access(i)

({A,B}, access(i), {A,B union {i}})

if i $\displaystyle \in$ A logical and $\displaystyle \exists$ j $\displaystyle \in$ A logical and i<>j (i not equal j)

If I write state change as above, the statements following "if" describe the Q1 correct? Or I should mention "if in Q1" and then write conditions?

Another question is do I need to write $\displaystyle \exists$ i $\displaystyle \in$ A
instead of i $\displaystyle \in$ A

Thank you

2. ## Re: State conditions - correct syntax

Originally Posted by Tina
({A,B}, access(i), {A,B union {i}})

if i $\displaystyle \in$ A logical and $\displaystyle \exists$ j $\displaystyle \in$ A logical and i<>j (i not equal j)

If I write state change as above, the statements following "if" describe the Q1 correct?
I am not sure what subject this is, so it's hard to say. What is the relationship between the first and the second line?

3. ## Re: State conditions - correct syntax

second line states the condition in Q1 implicitly (Not sure if I should explicitly say if in Q1). If these conditions are true, after performing the action, the system will have state Q2.

For example, if i=2, then we can move to state Q2 and in that state, we add i to B.

This type of state change is used in some programming lang and I/O automaton.

Thanks

4. ## Re: State conditions - correct syntax

It seems to me that whether you need to refer to Q1 explicitly depends on the syntax of the concrete programming language or formalism you are using. This is far from conventional logic, so it's hard to say in general.