Linear-Function Correcting Codes

In this paper, we study linear-function correcting codes, a class of codes designed to protect linear function evaluations of a message against errors. The work "Function-Correcting Codes" by Lenz et al. 2023 provides a graphical representation for the problem of constructing function-correcting codes. We use this graph to get a lower bound the on redundancy required for function correction. By considering the function to be a bijection, such an approach also provides a lower bound on the redundancy required for classical systematic error correcting codes. For linear-function correction, we characterise the spectrum of the adjacency matrix of this graph, which gives rise to lower bounds on redundancy. The work "Function-Correcting Codes" gives an equivalence between function-correcting codes and irregular-distance codes. We identify a structure imposed by linearity on the distance requirement of the equivalent irregular-distance code which provides a simplified Plotkin-like bound. We propose a version of the sphere packing bound for linear-function correcting codes. We identify a class of linear functions for which an upper bound proposed by Lenz et al., is tight. We also identify a class of functions for which coset-wise coding is equivalent to a lower dimensional classical error correction problem.