Thursday, January 1, 2009

Compendium of Peirce's Existential Graphs

Based on Zalamea. See also Zeman, Sowa and Dau.

p, q, f -- propositional letters
P, Q, F -- predicate letters

Alpha





Peirce's modified notationMy (modified) notation
pq -- conjunction(pq)
‹p› -- negation‹p›
‹p‹q›› -- implication[‹p›q]
‹‹p›‹q›› -- disjunction[pq]


A1 Erasure: Any evenly enclosed graph may be erased.
A2 Insertion: Any graph may be inserted in any oddly enclosed region.
A3 Iteration: Any graph may be iterated (i.e. repeated) in a strict region of that graph.
A4 Deiteration: Any graph whose occurrence could result from iteration may be deiterated (i.e. erased).
A5 Double cut: A double cut may be inserted or erased around any graph in any region.

A1 (ER): pq ⇒ p                                           (pq) ⇒ p
A2 (IN): ‹p› ⇒ ‹pq›                                 ‹p› ⇒ ‹pq›
A3, A4 (IT and DI): p‹q› ⇔ p‹pq›         (p‹q›) ⇔ (p‹pq›)
A5 (DC): p ⇔ ‹‹p››                                   p ⇔ ‹‹p››


Beta

LI -- Line of Identity

B1 Erasure: Any evenly enclosed portion of an LI may be erased.
B2 Insertion: Any portions of LI's may be joined in an oddly enclosed region.
B3 Continuous iteration: Any LI may be extended towards strict regions. Any LI may branch in its region.
B4 Continuous deiteration: Any LI may be retracted towards regions with lesser cuts.

B1: P---Q ⇒ P- -Q                                           (PQ)(P)(Q)
B2: ‹P- -Q› ⇒ ‹P---Q›                                ‹(P)(Q)› ⇒ ‹(PQ)
B3, B4: P--- ‹q› ⇔ P-‹- q›                           (P)‹q› ⇔ (P‹q›)?

Some X is R to every Y ⇒ To every Y some X is R.
-‹-‹-R2-›-› ⇒ ‹‹-R2-›-›            (X1[‹Y2›R12])[‹Y2›(X1R12)]?

Gamma

{f} -- possibly not f                                             (‹f›)
‹{f}› -- not possibly not f = necessarily f     ‹(‹f›)› = [f]
{‹f›} -- possibly not not f = possibly f            (‹‹f››) = (f)

‹{f}› ⇒ ‹‹f›› ⇒ f ⇒ ‹‹f›› ⇒ {‹f›}


G1: In an even area, any Alpha cut may be half-erased to become a Gamma cut.
‹› ⇒ {}                                                                ‹› ⇒ (‹›)
G2: In an odd area, any Gamma cut may be half-completed to become an Alpha cut.
‹{}› ⇒ ‹‹››                                                      ‹(‹›)› ⇒ ‹‹››