Rod Girle [2000] Modal Logics and Philosophy Chapter 3
S4 has the rules
{Non-modal propositional rules + Modal Negation + ◊R + □R+ □T+□□R}
These are described in Review of S4 Rules.
The extra rule (over T) is the Rule □□R and what it allows you to do it this. Without it (but with the other rules) you could reason from
□F (n)
Access(nw)
8/17/26
Rod Girle [2000] Modal Logics and Philosophy Chapter 3
T has the rules
{Non-modal propositional rules + Modal Negation + ◊R + □R+ □T}
These are described in Review of T Rules.
There are the ordinary (non-modal) tree propositional rules plus
The Modal Negation (MN) rules
Rod Girle [2000] Modal Logics and Philosophy Chapter 3
K has the rules
{Non-modal propositional rules + Modal Negation + ◊R + □R}
These are described in Review of K Rules.
There are the ordinary (non-modal) tree propositional rules plus
The Modal Negation (MN) rules
Rod Girle [2000] Modal Logics and Philosophy Chapter 3
The next step is to relativize necessity and possibility to Access. You can experiment with this...
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Rod Girle [2000] Modal Logics and Philosophy Chapter 2
You can make a reasonable start here by thinking about how truth tables might work once there are the modal operators, necessary □ and possible ◊.
10/3/08 10 Software under construction.
Close the following trees using S5. Then go to the Rule Set Menu and change the rules to K, then try to close the trees a second time.
10/3/08 10 Software, under construction.
Close the following trees using S5. Then go to the Rule Set Menu and change the rules to K, then try to close the trees a second time.