Trying to find an SF story

The punch line is that someone says “I want it Yesterday” and in fact some odd package had shown up in the mailbox yesterday without them realising it. The protagonists run a consulting agency offering mathematical help to companies. They say something like " A few lines of vector calculus can give you a result that would take pages of rusty algebra." I think one of the characters may be called ‘Sita Lal’, though I wouldn’t swear to that. Interestingly, none of the usual AIs can find it…?

Paging @Andy_L.

Or a mod to paste it into the “ask a guy” thread…

When I put that plot description into Google, it claims that the story is “The Mind Digger” by F.L. Wallace. I found a copy of the story online. It’s at The Project Gutenberg eBook of The Mind Digger, by Winston Marks. . Is that the story? I skimmed through it and it doesn’t look right.

Different story, clearly - but a good one (I’ve read it before). I don’t know what the OP’s story is, yet, but I’m thinking about it.

There is a story called “We Can Get It to You Yesterday

I get an error message from that link. Any other sources available?

maybe the short story “We Can Get It for You Wholesale” by Philip K. Dick. 1954, the protagonist discovers the existence of time-traveling telepaths—and decides to use their services for getting rich.
The protagonist is George Miller, a shipping clerk who learns that people from the future are sending items backwards in time to his period. Discovering that their service is really fast and cheap , George realizes he can cheat the stock market, place bets, etc.

https://www.isfdb.org/cgi-bin/title.cgi?2556930 is the right link

I bet it is Phillip K Dick, not Heather Morris.

That sounds like a garbling of the real Dick title, “We Can Remembe It For You Wholesale” with a story description from some other story.

Other notable adaptations include Total Recall (“We Can Get it for You Wholesale”),

But maybe I have gotten the precis wrong. Hmm. Weird.

But I cant find that title by Heather Morris either. I am getting too much wrong, I give up.

I don’t think any of the answers so far really match the OP.

I agree. I’m pretty sure it wasn’t Dick: doesn’t seem to match his style.

There were no telepaths in the story I remember, and time travel was definitely not an established thing in the story world…?

And having just looked up Heather Morris on Wikipedia, it doesn’t sound at all like her style either…?

Then how did the package arrive yesterday? That sure sounds like time travel…

Indeed, simply pasting your OP into Gemini produces output that isn’t helpful at all, but quite entertaining to read…

That’s the surprise punch line. Time travel is not a known thing in-story.

Ah, gotcha. It was a thing, but not an established thing.

I’m beginning to wonder if this is a sort of ‘Yesterday’-like dream… a story that only exists in my subconscious.

Except that I have a quite clear impression of having actually read the story…?