Amenable group actions on the integers; an independence result

A method for single well addressability in a sample processor with row and column feeds. A sample processor or chip has a matrix of reservoirs or wells arranged in columns and rows. Pressure or electrical pumping is utilized to fill the wells with materials. In a preferred embodiment, single well addressability is achieved by deprotecting a single column (row) and coupling each transverse row (column) independently. After the coupling step, the next column (row) is deprotected and then coupling via rows (columns) is performed. Each well can have a unique coupling event. In other embodiments, the chemical events could include, for example, oxidation, reduction or cell lysis.