WFF 'N PROOF:
The  Game of Modern Logic
By Layman E. Allen
Professor of Law and Senior Research Scientist, University of Michigan

Adventurous WFF 'N PROOF Strategies
Strategies of Constructing PROOFs and Strategies of Play *

1. Strategies of Constructing PROOFs

    A. Grand Strategy

        Try first to prove it directly; if that fails, try to prove it indirectly.
 

    Example 1A1.  To prove: NKNpq --** ApNq
. NKoAi: NKNpq --** ApNq
1|_NKNpq     s
2|a|_q       s        (Trying to prove Nq at 1st level,
 |b|1|_p     s         and then ApNq, by Ai)
 | |2| :
 | |3| q     aR
 | |4| Np    ?        (Fails at this step, as all other 
 | |5| KNpq  4,3,Ki    direct efforts will somehow fail)
 | |6| NKNpq 1RR
 |c| Np      b,Ni
 |d| KNpq    c,a,Ki
 |e| NKNpq   1R
3| Nq        2,Ni
4| ApNq      3,Ai

        Failed trying to prove it directly; so try proving it indirectly.
        In mathematical logic the No Rule is called the Rule of Indirect Proof; the Ni Rule is called Reductio ad Absurdum.
        So, try No.
 

NKoAi: NKNpq --** ApNq
1|_NKNpq         s
2|a|_NApNq       s
|b|1|_Np         s
| |2|a|_q        s
| | |b| KNpq     1R,a,Ki
| | |c| NKNpq    1RRR
| |3| Nq         2,Ni
| |4| ApNq       3,Ai
| |5| NApNq      aR
|c| p            b,No
|d| ApNq         c,Ai
|e| NApNq        a,Rp
3| ApNq          2,No

    B. C2A Conversion

    Where the 18 Basic Derived Rules are available for purposes of constructing proofs (in PC Proof -- Game 20 and
    Frantic WFF 'N PROOF -- Game 21), use C2A Conversion (the CoAi Rule) to transform the objective from getting to
    an A-WFF to getting to a C-WFF, and then getting to the A-WFF from the C-WFF by the CoAi Rule.
 

    Example 1B1.  To prove: NKNpq --** ApNq
. NKoAi: NKNpq --** ApNq
1|_NKNpq      s
2|a|_Np       s
 |b)1|_q      s
 | |2| KNpq   aR,1,Ki
 | |3| NKNpq  1RR
 |c| Nq       b,Ni
3| CNpNq      2,Ci
4| ApNq       3,CoAi

2. Strategies of Play -- The Devastating Duo: SSU and BAF

Here, there is a available a powerful Learning Program to gain mastery of these two strategies that every serious player of Adventurous WFF 'N PROOF should work through completely.
        A. SSU (Sneaky Snuggle Up)

        Example 2A1.     Given the Resources: CRR pps ...
                                    to set the Goal: Csp
                                    is a SSU, because by doing so you have snuggled up to within one move of being an A-Flub. Either
                                        1) transferring the remaining p to Permitted Premisses or Essential, or
                                        2) transferring a remaining R to Permitted Rules or Essential,
                                    on the next move will be an A-Flub.
 

Goal 
Solution
Proof of Goal from Solution
Csp  p/R(P2a1) P2A1: p --** Csp
1|_p      s
2|a|_s    s
 |b| p    1R
3| Csp    2,Ci

        Example 2A2.      Given the remaining Resources: AKNNNRR prqss ...
                                    with the Goal: KpANrNq
                                    and the already allocated Resources: Permitted Premisses:s Permitted Rules: Essential:
                                    to move an s to Essential is a DSU, because by doing so you have snuggled up to within one
                                    move of being an A-Flub. Either
                                            1) transferring a remaining N to Permitted Premisses or Essential, or
                                            2) transferring a remaining R to Permitted Rules or Essential,
                                    on the next move will be an A-Flub.
 

Goal 
Solution
Proof of Proved Rule
KpANrNq s,Ns/R(PR2A2) PR2A2: s,Ns --** KpANrNq
1| s            s
2|_Ns           s
3|a|_NKpANrNq   s
 |b| s          1R
 |c| Ns         2R
4| KpANrNq      3,No

        B. BAF (Bold A-Flub)

            Example 2B1.     Given the Resources: CCNNRR pps ...
                                        to set the Goal: CNCppNs
                                        may well be a BAF, because by doing so you have made an A-Flub.
 

Goal 
Solution
Proof of Proved Rule
CNCppNs /R(PR2B1) PR2B1: --** CNCppNs
1|a|_NCNCppNs   s
 |b| KNCppNNs   a,NCoKi
 |c| NCpp       b,Ko
 |d| KpNp       c,NCoKi
 |e| p          d,Ko
 |f| Np         d,Ko
2| CNCppNs      1,No

Remember,

Here, there is a available a powerful Learning Program to gain mastery of these two strategies that every serious player of Adventurous WFF 'N PROOF should work through completely.
If you notice any typographic errors or have any other suggestions for improving this web page, please notify me at the email address:
laymanal@umich.edu