I had always thought of mathematics as being much more straightforward: a formula is a formula, and an algebra is an algebra, but Gelfand found hedgehogs lurking in the rows of his spectral sequences!
I had palaging-iisip ng matematika bilang marami pa direstong: isang formula ay isang pormula, at isang algebra ay isang algebra, ngunit Gelfand natagpuan hedgehogs lingid sa mga hanay ng kanyang mga multo sequences!