• README ⤓ .txt 2026-07-17T121634.146 000000000000672
  Logics individuated by their treatment of the structural rules of the sequent calculus—weakening, contraction, exchange, and associativity. Restricting or removing these rules makes the logic sensitive to the multiplicity, order, and use of premises, turning assumptions into consumable resources.
• Affine
  Logics that drop the structural rule of contraction while retaining weakening.
• Linear
  Logics that drop both weakening and contraction, treating hypotheses as resources consumed exactly once, with the exponential modalities !
• Nontransitive
  Logics individuated by restricting or dropping cut—the transitivity of the consequence relation.
• Ordered
  Logics that drop the structural rule of exchange, so that the order of hypotheses is significant and cannot be permuted.
• Relevant
  Logics that drop weakening in order to enforce relevance: the antecedent of a valid implication must actually be used in deriving the consequent, blocking the paradoxes of material and strict implication.
• CRITERIA ⤓ .txt 2026-07-15T233655.000 000000000009608
  An entry belongs in this division if and only if it is individuated by the restriction, removal, or fine control of one or more structural rules—weakening, contraction, exchange, associativity, or cut. Transitivity of consequence is a structural rule, and a logic individuated by dropping it belongs here however classical it is otherwise.