We prove upper and lower bounds on the size of the largest square grid graph that is a subgraph, minor, or shallow minor of a graph in the form of a larger square grid from which a specified number of vertices have been deleted. Our bounds are tight to within constant factors. We also provide less-tight bounds on analogous problems for higher-dimensional grids.

Our goal in writ ing “Dam aged Mer chan dise?” (DM) was not to have the last word on the sub ject but to raise an aware ness within the hu man–com puter in ter ac tion (HCI) com mu nity of is sues that we felt had been too long ig nored or ne glected. On read ing the 10 com men tar ies from dis tin guished mem bers of the HCI com mu nity, we were pleased to see that they had joined the de bate ...