Yes, sinc(x) is non-negative definite, because its Fourier Tran

Yes, sinc(x) is non-negative definite, because its Fourier Transform, FT(sinc(x)), is non-negative.

If it sounds "joke" to you, you need to dust off your math textbook.

:)

所有跟帖： 

• Bochner calls it "positive definite", not "NND". Get a better te -weston- ♀ (0 bytes) () 03/07/2015 postreply 06:56:21

• FT(sinc(x)) becomes zero at lots of points, doesn't it? -career- ♂ (53 bytes) () 03/07/2015 postreply 07:06:36

• Sigh. You don't understand the proof of the Bochner Theorem. Go -weston- ♀ (0 bytes) () 03/07/2015 postreply 09:05:12

• You don't need more "proof"--it's by the definition! :) -career- ♂ (0 bytes) () 03/07/2015 postreply 09:15:36

• Surprised anyway would hire someone like you who doesn't know -weston- ♀ (78 bytes) () 03/07/2015 postreply 09:44:02

• You forgot any integral over a zero-valued set yields zero. :) -career- ♂ (62 bytes) () 03/07/2015 postreply 11:18:28

• Your step function is not zero over an open interval. Check Four -weston- ♀ (0 bytes) () 03/07/2015 postreply 11:21:46

• It's a rectangular function--not a "step"! -career- ♂ (67 bytes) () 03/07/2015 postreply 11:33:18

• Wikipedia "rectangular function, the next simplest step function -weston- ♀ (0 bytes) () 03/07/2015 postreply 11:40:53

• hoho, you even need Wiki for that! :) -career- ♂ (168 bytes) () 03/07/2015 postreply 11:46:47

• For your conenience only, since you had idea step functions cove -weston- ♀ (0 bytes) () 03/07/2015 postreply 11:57:00

• I have the rectangular. it is you who "mis"-"step":))) -career- ♂ (567 bytes) () 03/07/2015 postreply 11:59:34

• 你这是 "白马非马" 的现代版 -weston- ♀ (0 bytes) () 03/07/2015 postreply 12:03:16

• Stay in math,pls. :) -career- ♂ (0 bytes) () 03/07/2015 postreply 12:19:30