Alphabeta Math

Tensor Products of Modules — Examples

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How statement and proof provenance work

The first chip identifies the source of the statement or construction; the second identifies the source of its local proof or verification.

  • Literature-sourced: the exact statement appears in a cited source; only wording and notation differ.
  • AI-adapted: a semantically identical restatement of literature-sourced material, modulo indexing, notation, and boundary cases adopted by the library.
  • AI-generated: a genuinely novel statement formulated by AI, with no source for the claim itself.

These labels describe origin, not correctness: citations and verification chips remain separate evidence.

✓ 11 results · all verified · 2 also independently AI-judged
Every result on this page is machine-checked by a proof checker and read in full and owner-audited; the judge is an additional, independent cross-model AI review of the proofs. The 9 not AI-judged were verified by owner audit (typically over a confirmed judge false positive), not failures.
1 · Prerequisites
2 · Logical flowchart

3 · Items

False statement

False: ℤ/m⊗_ℤℤ/n is nonzero for all positive m,n

Example

ℚ⊗_ℤℤ/n=0 for every positive n

Example

(R/I)⊗_R(R/J)≅ R/(I+J) for ideals of a commutative ring

Example

S⊗_RR[x]≅ S[x] as S-algebras

Example

For a field extension K/F, one has K⊗_FMₙ(F)≅ Mₙ(K) as K-algebras

Example

For a field extension K/F, one has K⊗_FFⁿ≅ Kⁿ

Example

ℂ⊗_ℝℂ≅ℂ×ℂ as ℝ-algebras

Example

Tensoring the injection k[x] →(· x) k[x] with k[x]/(x) gives the zero map

False statement

False: m⊗ n=0 implies m=0 or n=0

False statement

False: every element of M⊗_RN is an elementary tensor

False statement

False: tensoring preserves injections

Sources