SHA256 and RIPEMD160 collisions

[coder0x15]

H = ripemd160(sha256(ECMultiply(A,G)))

A - 32-byte number,

H - 20-byte number,

G - generator point,

ECMultiply - elliptic curve point multiplication.

Is it true that there is many A that have the same H?

[amaclin1]

yes
https://en.wikipedia.org/wiki/Pigeonhole_principle

[efeaydin]

H = ripemd160(sha256(ECMultiply(A,G)))

A - 32-byte number,

H - 20-byte number,

G - generator point,

ECMultiply - elliptic curve point multiplication.

Is it true that there is many A that have the same H?

Yes, it is possible but the possibility is too low.

SHA256 hashes are almost unique. I don't think that anyone has found a SHA256.