A computerized spreadsheet system includes a set of cells and a separate set of logical constraints on the values of cells. The constraints may be many-to-many relationships that permit omni-directional propagation of values between cells. The constraints may be expressed in a language encompassing first-order logic. Cells are dynamically reclassified as base cells or computed cells as a user specifies values for cells. Non-explosive consequences of the base cell values are computed and displayed in computed cells, even when the values in the base cells are inconsistent with the constraints. The spreadsheet system may also include an auto-complete feature that automatically fills in empty cells with values consistent with the logical constraints and an auto-deconflict feature that automatically changes values in cells to reduce conflicts with the logical constraints.