is_subcover

std.topology.is_subcover · Level L1

Whether the members of a cover C selected by sel (a 0/1 mask over the members, so a subcover takes members of the original cover only) still contain K, as 1 or 0.

K ⊆ ∪{C_i : sel_i = 1}

Signature

is_subcover(C: f64[c, n], sel: f64[c], K: f64[n]) → f64[]

Structure

The function as NOVA stores it: one box per input, operation and output, and arrows that carry values. A double border marks another library function this one runs — called once, or by Scan once per element; select it to open that function.

input
operation
constant
call
output

Verification

Signature proven by NOVA’s shape solver, for every size.
Equal to the reference K inside the union of the selected rows in exact rational arithmetic, on all 40 test cases.
All 40 float64 results are exact: the error is zero.
Interpreter and NumPy backend return bit-identical results.
At float32 too: the 40 test cases rounded to float32, and 40 of them exact, with zero error.

Accuracy in detail

correctly rounded (the float64 nearest the exact value): 100%
bit-equal to the NumPy formula in float64: 100%
largest error, in units in the last place: 0

Identity

Calls

—

Called by

—

sha256:25ebf750557f20b63ac6532bf01749e91ee6d2dd0ea83670c98c7c0f06317778

The semantic hash of the graph. It changes when the program changes, and never when only its documentation does.

Control handle

Symbol: Ω:std.topology.is_subcover · Ω:is_subcover
Pins: sha256:862272c2c6e57f5bb545c5ee77cea0e9dc3892fdb2e1811f4ecb988412bae3e1this graph alone
Evidence: sha256:7d8087fca3671f13829c7f09e903b03f28c0aee5a1ecfded126afbf6a60d14b6the hash of its verification record
Needs: no capability: a pure function

Through NOVA’s control layer, the symbol launches this function only while the program still matches what it pins: a change to this graph, or to any graph it reaches, needs a migration first.