Post #2437630

2026-04-27 15:11 UTC

@mxp@mastodon.acm.org @tomstoneham@dair-community.social “I don't know much about image editing, so I assume you are right.” no need to believe me, Tom- here’s a simple example: imagine an irregular object of your choice, now imagine stretching it along the horizontal axis, then rotate it. Contrast the result with the order 1) rotate 2) stretch….

Replies (2)

@UlrikeHahn@fediscience.org 2026-04-27 15:31

@mxp@mastodon.acm.org @tomstoneham@dair-community.social actually, I think I have now understood the source of (my!) error - the “chain” consists of strung together immediate forward/backward steps not concatenation of steps and their undoing? so linear transformations would be fine as one is only ever doing and undoing one operation at a time? that would still leave the original problem of potential ambiguity in the instructions (add/remove Rembrandt lighting?) (though non-commutativity across individual operations would still play an indirect role as it would amplify the emergence of differences, ie it makes it the case that errors interact?)

Open ##2437631
@tomstoneham@dair-community.social 2026-04-27 16:09

@UlrikeHahn@fediscience.org @mxp@mastodon.acm.org Ah. I was imagining a situation where you stretch then rotate, then reverse the stretch without first reversing the rotation. That would be what I had in mind for 2).

Open ##2437638