# 02 — Problem Contracts v0.1
## PC01 Preservation — FROZEN
Specify subject/type, transformation structure, criterion, preserved feature/relation, tolerance, scope, and whether pairwise/path/lineage structure matters. Used by RP003/RP004.

## PC02 Representation Sufficiency — FROZEN
Specify source, representation, inquiry/action family, distinctions to preserve, permitted collapses, resource assumptions and excluded future inquiries. Sufficiency is query-relative unless a stronger result is established. Used by RP002A/Research Graph.

## PC03 Reachability — FROZEN
Specify source, targets, transformations, applicability/admissibility, constraints/resources, horizon, policy and viability criterion. Used by RP005A.

Draft only: PC04 Revision; PC05 Relational Sufficiency; PC06 Structural Transfer.